Programs & Examples On #Csvde

csvde is a Windows command which imports or exports user data from the Active Directory server.

List of enum values in java

An enum is just another class in Java, it should be possible.

More accurately, an enum is an instance of Object:

So yes, it should work.

What is IllegalStateException?

Usually, IllegalStateException is used to indicate that "a method has been invoked at an illegal or inappropriate time." However, this doesn't look like a particularly typical use of it.

The code you've linked to shows that it can be thrown within that code at line 259 - but only after dumping a SQLException to standard output.

We can't tell what's wrong just from that exception - and better code would have used the original SQLException as a "cause" exception (or just let the original exception propagate up the stack) - but you should be able to see more details on standard output. Look at that information, and you should be able to see what caused the exception, and fix it.

What's the difference between .NET Core, .NET Framework, and Xamarin?

You should use .NET Core, instead of .NET Framework or Xamarin, in the following 6 typical scenarios according to the documentation here.

1. Cross-Platform needs

Clearly, if your goal is to have an application (web/service) that should be able to run across platforms (Windows, Linux and MacOS), the best choice in the .NET ecosystem is to use .NET Core as its runtime (CoreCLR) and libraries are cross-platform. The other choice is to use the Mono Project.

Both choices are open source, but .NET Core is directly and officially supported by Microsoft and will have a heavy investment moving forward.

When using .NET Core across platforms, the best development experience exists on Windows with the Visual Studio IDE which supports many productivity features including project management, debugging, source control, refactoring, rich editing including Intellisense, testing and much more. But rich development is also supported using Visual Studio Code on Mac, Linux and Windows including intellisense and debugging. Even third party editors like Sublime, Emacs, VI and more work well and can get editor intellisense using the open source Omnisharp project.

2. Microservices

When you are building a microservices oriented system composed of multiple independent, dynamically scalable, stateful or stateless microservices, the great advantage that you have here is that you can use different technologies/frameworks/languages at a microservice level. That allows you to use the best approach and technology per micro areas in your system, so if you want to build very performant and scalable microservices, you should use .NET Core. Eventually, if you need to use any .NET Framework library that is not compatible with .NET Core, there’s no issue, you can build that microservice with the .NET Framework and in the future you might be able to substitute it with the .NET Core.

The infrastructure platform you could use are many. Ideally, for large and complex microservice systems, you should use Azure Service Fabric. But for stateless microservices you can also use other products like Azure App Service or Azure Functions.

Note that as of June 2016, not every technology within Azure supports the .NET Core, but .NET Core support in Azure will be increasing dramatically now that .NET Core is RTM released.

3. Best performant and scalable systems

When your system needs the best possible performance and scalability so you get the best responsiveness no matter how many users you have, then is where .NET Core and ASP.NET Core really shine. The more you can do with the same amount of infrastructure/hardware, the richer the experience you’ll have for your end users – at a lower cost.

The days of Moore’s law performance improvements for single CPUs does not apply anymore; yet you need to do more while your system is growing and need higher scalability and performance for everyday’ s more demanding users which are growing exponentially in numbers. You need to get more efficient, optimize everywhere, and scale better across clusters of machines, VMs and CPU cores, ultimately. It is not just a matter of user’s satisfaction; it can also make a huge difference in cost/TCO. This is why it is important to strive for performance and scalability.

As mentioned, if you can isolate small pieces of your system as microservices or any other loosely-coupled approach, it’ll be better as you’ll be able to not just evolve each small piece/microservice independently and have a better long-term agility and maintenance, but also you’ll be able to use any other technology at a microservice level if what you need to do is not compatible with .NET Core. And eventually you’d be able to refactor it and bring it to .NET Core when possible.

4. Command line style development for Mac, Linux or Windows.

This approach is optional when using .NET Core. You can also use the full Visual Studio IDE, of course. But if you are a developer that wants to develop with lightweight editors and heavy use of command line, .NET Core is designed for CLI. It provides simple command line tools available on all supported platforms, enabling developers to build and test applications with a minimal installation on developer, lab or production machines. Editors like Visual Studio Code use the same command line tools for their development experiences. And IDE’s like Visual Studio use the same CLI tools but hide them behind a rich IDE experience. Developers can now choose the level they want to interact with the tool chain from CLI to editor to IDE.

5. Need side by side of .NET versions per application level.

If you want to be able to install applications with dependencies on different versions of frameworks in .NET, you need to use .NET Core which provides 100% side-by side as explained previously in this document.

6. Windows 10 UWP .NET apps.

In addition, you may also want to read:

  1. When should I NOT use .NET Core?
  2. When should I still use .NET Framework 4.x, instead of .NET Core?
  3. When should I use Xamarin, instead of .NET Core?

How to resolve "Input string was not in a correct format." error?

Because Label1.Text is holding Label which can't be parsed into integer, you need to convert the associated textbox's text to integer

imageWidth = 1 * Convert.ToInt32(TextBox2.Text);

Android Studio don't generate for my import project

Just use the 'Rebuild Project' from the 'Build' menu from the top menu bar.

How to show PIL images on the screen?

You can display an image in your own window using Tkinter, w/o depending on image viewers installed in your system:

import Tkinter as tk
from PIL import Image, ImageTk  # Place this at the end (to avoid any conflicts/errors)

window = tk.Tk()
#window.geometry("500x500") # (optional)    
imagefile = {path_to_your_image_file}
img = ImageTk.PhotoImage(
lbl = tk.Label(window, image = img).pack()

For Python 3, replace import Tkinter as tk with import tkinter as tk.

What is the Python 3 equivalent of "python -m SimpleHTTPServer"

The equivalent is:

python3 -m http.server

List supported SSL/TLS versions for a specific OpenSSL build

It's clumsy, but you can get this from the usage messages for s_client or s_server, which are #ifed at compile time to match the supported protocol versions. Use something like

 openssl s_client -help 2>&1 | awk '/-ssl[0-9]|-tls[0-9]/{print $1}' 
 # in older releases any unknown -option will work; in 1.1.0 must be exactly -help

How to access shared folder without giving username and password

I found one way to access the shared folder without giving the username and password.

We need to change the share folder protect settings in the machine where the folder has been shared.

Go to Control Panel > Network and sharing center > Change advanced sharing settings > Enable Turn Off password protect sharing option.

By doing the above settings we can access the shared folder without any username/password.

how to determine size of tablespace oracle 11g

One of the way is Using below sql queries

--Size of All Table Space

--1. Used Space
--2. Free Space

--3. Both Free & Used

Utils to read resource text file to String (Java)

Here's a solution using Java 11's Files.readString:

public class Utils {
    public static String readResource(String name) throws URISyntaxException, IOException {
        var uri = Utils.class.getResource("/" + name).toURI();
        var path = Paths.get(uri);
        return Files.readString(path);

How to set HttpResponse timeout for Android in Java

If you are using the HttpURLConnection, call setConnectTimeout() as described here:

URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();

Git: Cannot see new remote branch

You can checkout remote branch /n git fetch && git checkout remotebranch

How to try convert a string to a Guid

Unfortunately, there isn't a TryParse() equivalent. If you create a new instance of a System.Guid and pass the string value in, you can catch the three possible exceptions it would throw if it is invalid.

Those are:

  • ArgumentNullException
  • FormatException
  • OverflowException

I have seen some implementations where you can do a regex on the string prior to creating the instance, if you are just trying to validate it and not create it.

What is the correct way to do a CSS Wrapper?

Are there other ways?

Negative margins were also used for horizontal (and vertical!) centering but there are quite a few drawbacks when you resize the window browser: no window slider; the content can't be seen anymore if the size of the window browser is too small.
No surprise as it uses absolute positioning, a beast never completely tamed!


So that was only FYI as you asked for it, margin: 0 auto; is a better solution.

Do I need a content-type header for HTTP GET requests?

Short answer: Most likely, no you do not need a content-type header for HTTP GET requests. But the specs does not seem to rule out a content-type header for HTTP GET, either.

Supporting materials:

  1. "Content-Type" is part of the representation (i.e. payload) metadata. Quoted from RFC 7231 section 3.1:

    3.1. Representation Metadata

    Representation header fields provide metadata about the representation. When a message includes a payload body, the representation header fields describe how to interpret the representation data enclosed in the payload body. ...

    The following header fields convey representation metadata:

    | Header Field Name | Defined in...   |
    | Content-Type      | Section |
    | ...               | ...             |

    Quoted from RFC 7231 section the way, the current chosen answer had a typo in the section number):

    The "Content-Type" header field indicates the media type of the associated representation

  2. In that sense, a Content-Type header is not really about an HTTP GET request (or a POST or PUT request, for that matter). It is about the payload inside such a whatever request. So, if there will be no payload, there needs no Content-Type. In practice, some implementation went ahead and made that understandable assumption. Quoted from Adam's comment:

    "While ... the spec doesn't say you can't have Content-Type on a GET, .Net seems to enforce it in it's HttpClient. See this SO q&a."

  3. However, strictly speaking, the specs itself does not rule out the possibility of HTTP GET contains a payload. Quoted from RFC 7231 section 4.3.1:

    4.3.1 GET


    A payload within a GET request message has no defined semantics; sending a payload body on a GET request might cause some existing implementations to reject the request.

    So, if your HTTP GET happens to include a payload for whatever reason, a Content-Type header is probably reasonable, too.

How to achieve pagination/table layout with Angular.js?

I would use table and implement the pagination in the controller to control how much is shown and buttons to move to the next page. This Fiddle might help you.

example of the pagination

 <table class="table table-striped table-condensed table-hover">
                        <th class="id">Id&nbsp;<a ng-click="sort_by('id')"><i class="icon-sort"></i></a></th>
                        <th class="name">Name&nbsp;<a ng-click="sort_by('name')"><i class="icon-sort"></i></a></th>
                        <th class="description">Description&nbsp;<a ng-click="sort_by('description')"><i class="icon-sort"></i></a></th>
                        <th class="field3">Field 3&nbsp;<a ng-click="sort_by('field3')"><i class="icon-sort"></i></a></th>
                        <th class="field4">Field 4&nbsp;<a ng-click="sort_by('field4')"><i class="icon-sort"></i></a></th>
                        <th class="field5">Field 5&nbsp;<a ng-click="sort_by('field5')"><i class="icon-sort"></i></a></th>
                    <td colspan="6">
                        <div class="pagination pull-right">
                                <li ng-class="{disabled: currentPage == 0}">
                                    <a href ng-click="prevPage()">« Prev</a>
                                <li ng-repeat="n in range(pagedItems.length)"
                                    ng-class="{active: n == currentPage}"
                                    <a href ng-bind="n + 1">1</a>
                                <li ng-class="{disabled: currentPage == pagedItems.length - 1}">
                                    <a href ng-click="nextPage()">Next »</a>
                    <tr ng-repeat="item in pagedItems[currentPage] | orderBy:sortingOrder:reverse">

the $scope.range in the fiddle example should be:

$scope.range = function (size,start, end) {
    var ret = [];        
    console.log(size,start, end);

       if (size < end) {
        end = size;
             start = 0;
             start = size-$;

    for (var i = start; i < end; i++) {
    return ret;

Example of SOAP request authenticated with WS-UsernameToken

Check this one (Password should be password):

<wsse:UsernameToken xmlns:wsu="" wsu:Id="SecurityToken-6138db82-5a4c-4bf7-915f-af7a10d9ae96">
  <wsse:Password Type="">CBb7a2itQDgxVkqYnFtggUxtuqk=</wsse:Password>

How do you post to an iframe?

If you want to change inputs in an iframe then submit the form from that iframe, do this

var el = document.getElementById('targetFrame');

var doc, frame_win = getIframeWindow(el); // getIframeWindow is defined below

if (frame_win) {
  doc = (window.contentDocument || window.document);

if (doc) {
  doc.forms[0].someInputName.value = someValue;

Normally, you can only do this if the page in the iframe is from the same origin, but you can start Chrome in a debug mode to disregard the same origin policy and test this on any page.

function getIframeWindow(iframe_object) {
  var doc;

  if (iframe_object.contentWindow) {
    return iframe_object.contentWindow;

  if (iframe_object.window) {
    return iframe_object.window;

  if (!doc && iframe_object.contentDocument) {
    doc = iframe_object.contentDocument;

  if (!doc && iframe_object.document) {
    doc = iframe_object.document;

  if (doc && doc.defaultView) {
   return doc.defaultView;

  if (doc && doc.parentWindow) {
    return doc.parentWindow;

  return undefined;

Python os.path.join on Windows

For a system-agnostic solution that works on both Windows and Linux, no matter what the input path, one could use os.path.join(os.sep, rootdir + os.sep, targetdir)

On WIndows:

>>> os.path.join(os.sep, "C:" + os.sep, "Windows")

On Linux:

>>> os.path.join(os.sep, "usr" + os.sep, "lib")

LINQ Using Max() to select a single row

Simply in one line:

var result = table.First(x => x.Status == table.Max(y => y.Status));

Notice that there are two action. the inner action is for finding the max value, the outer action is for get the desired object.

Spring Security with roles and permissions

After reading this post, from Baeldung. I found that the solution is pretty simple.

What I have done, is to add the role and permissions into the GrantedAuthority. I was able to access both methods hasRole() and hasAuthority().

What are all codecs and formats supported by FFmpeg?

Codecs proper:

ffmpeg -codecs


ffmpeg -formats

How to rename array keys in PHP?

Very simple approach to replace keys in a multidimensional array, and maybe even a bit dangerous, but should work fine if you have some kind of control over the source array:

$array = [ 'oldkey' => [ 'oldkey' => 'wow'] ];
$new_array = json_decode(str_replace('"oldkey":', '"newkey":', json_encode($array)));
print_r($new_array); // [ 'newkey' => [ 'newkey' => 'wow'] ]

How to automatically generate a stacktrace when my program crashes

For Linux and I believe Mac OS X, if you're using gcc, or any compiler that uses glibc, you can use the backtrace() functions in execinfo.h to print a stacktrace and exit gracefully when you get a segmentation fault. Documentation can be found in the libc manual.

Here's an example program that installs a SIGSEGV handler and prints a stacktrace to stderr when it segfaults. The baz() function here causes the segfault that triggers the handler:

#include <stdio.h>
#include <execinfo.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>

void handler(int sig) {
  void *array[10];
  size_t size;

  // get void*'s for all entries on the stack
  size = backtrace(array, 10);

  // print out all the frames to stderr
  fprintf(stderr, "Error: signal %d:\n", sig);
  backtrace_symbols_fd(array, size, STDERR_FILENO);

void baz() {
 int *foo = (int*)-1; // make a bad pointer
  printf("%d\n", *foo);       // causes segfault

void bar() { baz(); }
void foo() { bar(); }

int main(int argc, char **argv) {
  signal(SIGSEGV, handler);   // install our handler
  foo(); // this will call foo, bar, and baz.  baz segfaults.

Compiling with -g -rdynamic gets you symbol info in your output, which glibc can use to make a nice stacktrace:

$ gcc -g -rdynamic ./test.c -o test

Executing this gets you this output:

$ ./test
Error: signal 11:

This shows the load module, offset, and function that each frame in the stack came from. Here you can see the signal handler on top of the stack, and the libc functions before main in addition to main, foo, bar, and baz.

How can I create an Asynchronous function in Javascript?

If you want to use Parameters and regulate the maximum number of async functions you can use a simple async worker I've build:

var BackgroundWorker = function(maxTasks) {
    this.maxTasks = maxTasks || 100;
    this.runningTasks = 0;
    this.taskQueue = [];

/* runs an async task */
BackgroundWorker.prototype.runTask = function(task, delay, params) {
    var self = this;
    if(self.runningTasks >= self.maxTasks) {
        self.taskQueue.push({ task: task, delay: delay, params: params});
    } else {
        self.runningTasks += 1;
        var runnable = function(params) {
            try {
            } catch(err) {
        // this approach uses current standards:
        setTimeout(runnable, delay, params);

BackgroundWorker.prototype.taskCompleted = function() {
    this.runningTasks -= 1;

    // are any tasks waiting in queue?
    if(this.taskQueue.length > 0) {
        // it seems so! let's run it x)
        var taskInfo = this.taskQueue.splice(0, 1)[0];
        this.runTask(taskInfo.task, taskInfo.delay, taskInfo.params);

You can use it like this:

var myFunction = function() {
var myFunctionB = function() {
var myParams = { name: "John" };

var bgworker = new BackgroundWorker();
bgworker.runTask(myFunction, 0, myParams);
bgworker.runTask(myFunctionB, 0, null);

Xcode 9 Swift Language Version (SWIFT_VERSION)

Answer to your question:
You can download Xcode 8.x from Apple Download Portal or Download Xcode 8.3.3 (or see: Where to download older version of Xcode), if you've premium developer account (apple id). You can install & work with both Xcode 9 and Xcode 8.x in single (mac) system. (Make sure you've Command Line Tools supporting both version of Xcode, to work with terminal (see: How to install 'Command Line Tool'))

Hint: How to migrate your code Xcode 9 compatible Swift versions (Swift 3.2 or 4)
Xcode 9 allows conversion/migration from Swift 3.0 to Swift 3.2/4.0 only. So if current version of Swift language of your project is below 3.0 then you must migrate your code in Swift 3 compatible version Using Xcode 8.x.

This is common error message that Xcode 9 shows if it identifies Swift language below 3.0, during migration.

enter image description here

Swift 3.2 is supported by Xcode 9 & Xcode 8 both.

Project ? (Select Your Project Target) ? Build Settings ? (Type 'swift' in Searchbar) Swift Compiler Language ? Swift Language Version ? Click on Language list to open it.

enter image description here

Convert your source code from Swift 2.0 to 3.2 using Xcode 8 and then continue with Xcode 9 (Swift 3.2 or 4).

For easier migration of your code, follow these steps: (it will help you to convert into latest version of swift supported by your Xcode Tool)

Xcode: Menus: Edit ? Covert ? To Current Swift Syntax

enter image description here

How to reload a page using JavaScript

You can simply use


where document.URL gets the current page URL and window.location reloads it.

Basic example for sharing text or image with UIActivityViewController in Swift

I've used the implementation above and just now I came to know that it doesn't work on iPad running iOS 13. I had to add these lines before present() call in order to make it work

//avoiding to crash on iPad
if let popoverController = activityViewController.popoverPresentationController {
     popoverController.sourceRect = CGRect(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height / 2, width: 0, height: 0)
     popoverController.sourceView = self.view
     popoverController.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)

That's how it works for me

func shareData(_ dataToShare: [Any]){

        let activityViewController = UIActivityViewController(activityItems: dataToShare, applicationActivities: nil)

        //exclude some activity types from the list (optional)
        //activityViewController.excludedActivityTypes = [

        //avoiding to crash on iPad
        if let popoverController = activityViewController.popoverPresentationController {
            popoverController.sourceRect = CGRect(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height / 2, width: 0, height: 0)
            popoverController.sourceView = self.view
            popoverController.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)

        self.present(activityViewController, animated: true, completion: nil)

What is the best way to declare global variable in Vue.js?

In vue cli-3 You can define the variable in main.js like


And you can also access this variable in any component by using the the window.basurl

Change value of input placeholder via model?

You can bind with a variable in the controller:

<input type="text" ng-model="inputText" placeholder="{{somePlaceholder}}" />

In the controller:

$scope.somePlaceholder = 'abc';

Browser detection

Try the below code

HttpRequest req = System.Web.HttpContext.Current.Request
string browserName = req.Browser.Browser;

How to get current SIM card number in Android?

You have everything right, but the problem is with getLine1Number() function.

getLine1Number()- this method returns the phone number string for line 1, i.e the MSISDN for a GSM phone. Return null if it is unavailable.

this method works only for few cell phone but not all phones.

So, if you need to perform operations according to the sim(other than calling), then you should use getSimSerialNumber(). It is always unique, valid and it always exists.

Get access to parent control from user control - C#

According to Ruskins answer and the comments here I came up with the following (recursive) solution:

public static T GetParentOfType<T>(this Control control) where T : class
    if (control?.Parent == null)
        return null;

    if (control.Parent is T parent)
        return parent;

    return GetParentOfType<T>(control.Parent);

Tomcat manager/html is not available?

Your website is blank because ROOT directory is missing from your ../webapps folder. Refer to tomcat documentation for the specific location on where it should be.

Get source JARs from Maven repository

if you're using eclipse you could also open Preferences > Maven and select Download Artifact Sources, this would let the pom.xml intact and keep your sources or java docs (if selected) just for development right at your machine location ~/.m2

Excel VBA For Each Worksheet Loop

Try this more succinct code:

Sub LoopOverEachColumn()
    Dim WS As Worksheet
    For Each WS In ThisWorkbook.Worksheets
        ResizeColumns WS
    Next WS
End Sub

Private Sub ResizeColumns(WS As Worksheet)
    Dim StrSize As String
    Dim ColIter As Long
    StrSize = "20.14;9.71;35.86;30.57;23.57;21.43;18.43;23.86;27.43;36.71;30.29;31.14;31;41.14;33.86"
    For ColIter = 1 To 15
        WS.Columns(ColIter).ColumnWidth = Split(StrSize, ";")(ColIter - 1)
    Next ColIter
End Sub

If you want additional columns, just change 1 to 15 to 1 to X where X is the column index of the column you want, and append the column size you want to StrSize.

For example, if you want P:P to have a width of 25, just add ;25 to StrSize and change ColIter... to ColIter = 1 to 16.

Hope this helps.

How to get array keys in Javascript?

... ????

Alternatively, if you have a list of items you want to use...

var range = [46, 66, 90]
    , widthRange=[]
    , write=[];

    widthRange[46] = { min:0, max:52 }; 
    widthRange[66] = { min:52, max:70 }; 
    widthRange[90] = { min:70, max:94 }; 

for(var x=0; x<range.length; x++){var key, wr;

    key = range[x];

    wr = widthRange[key] || false;


    write.push(['key: #',key, ', min: ', wr.min, 'max:', wr.max].join(''));


pip connection failure: cannot fetch index base URL

I found the solutions from Daniel F and mattdedek very helpful: use an https URL, and upgrade pip in order to make that the default. But that still didn't fix the problem for me. I had this error, under Mac OS X / Python 3.4:

$ pip3 install Flask
Downloading/unpacking Flask
  Cannot fetch index base URL
  Could not find any downloads that satisfy the requirement Flask
Cleaning up...
No distributions at all found for Flask
Storing debug log for failure in /Users/huttarl/.pip/pip.log

and pip.log basically showed the same thing:

  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/pip/", line 277, in find_requirement
    raise DistributionNotFound('No distributions at all found for %s' % req) 
pip.exceptions.DistributionNotFound: No distributions at all found for Flask

With help from a friend, I learned that upgrading from Python 3.4 to 3.8 fixed the problem. Apparently this is because one of the newer versions of Python 3 included updated certificates:

Certificate verification and OpenSSL

This package includes its own private copy of OpenSSL 1.1.1. The trust certificates in system and user keychains managed by the Keychain Access application and the security command line utility are not used as defaults by the Python ssl module. A sample command script is included in /Applications/Python 3.8 to install a curated bundle of default root certificates from the third-party certifi package ( Double-click on Install Certificates to run it.

The bundled pip has its own default certificate store for verifying download connections.

After this upgrade, and running Install Certificates.command, the pip3 install Flask runs successfully.

You may have already upgraded to Python 3.6+ in Mac OS, and just overlooked this certificate installation command. In that case, browse to Applications/Python 3.x and double-click Install Certificates.command. (See Mac OSX python ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749))

Maintaining the final state at end of a CSS3 animation

IF NOT USING THE SHORT HAND VERSION: Make sure the animation-fill-mode: forwards is AFTER the animation declaration or it will not work...

animation-fill-mode: forwards;
animation-name: appear;
animation-duration: 1s;
animation-delay: 1s;


animation-name: appear;
animation-duration: 1s;
animation-fill-mode: forwards;
animation-delay: 1s;

How to use OR condition in a JavaScript IF statement?

Just use ||

if (A || B) { your action here }

Note: with string and number. It's more complicated.

Check this for deep understading:

Remove all non-"word characters" from a String in Java, leaving accented characters?

You might want to remove the accents and diacritic signs first, then on each character position check if the "simplified" string is an ascii letter - if it is, the original position shall contain word characters, if not, it can be removed.

:not(:empty) CSS selector is not working?

 border: 1px red solid;

// or 

 border: 1px red solid;

How do I find out which settings.xml file maven is using

Use the Maven debug option, ie mvn -X :

Apache Maven 3.0.3 (r1075438; 2011-02-28 18:31:09+0100)
Maven home: /usr/java/apache-maven-3.0.3
Java version: 1.6.0_12, vendor: Sun Microsystems Inc.
Java home: /usr/java/jdk1.6.0_12/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "2.6.32-32-generic", arch: "i386", family: "unix"
[INFO] Error stacktraces are turned on.
[DEBUG] Reading global settings from /usr/java/apache-maven-3.0.3/conf/settings.xml
[DEBUG] Reading user settings from /home/myhome/.m2/settings.xml

In this output, you can see that the settings.xml is loaded from /home/myhome/.m2/settings.xml.

How to update values in a specific row in a Python Pandas DataFrame?

Update null elements with value in the same location in other. Combines a DataFrame with other DataFrame using func to element-wise combine columns. The row and column indexes of the resulting DataFrame will be the union of the two.

df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
     A    B
0  1.0  3.0
1  0.0  4.0

more information in this link

Create PDF from a list of images

I had the same problem, so I created a python function to unite multiple pictures in one pdf. The code (available from my github page, uses reportlab, and is based on answers from the following links:

Here is example of how to unite images into pdf:

We have folder "D:\pictures" with pictures of types png and jpg, and we want to create file pdf_with_pictures.pdf out of them and save it in the same folder.

outputPdfName = "pdf_with_pictures"
pathToSavePdfTo = "D:\\pictures"
pathToPictures = "D:\\pictures"
splitType = "none"
numberOfEntitiesInOnePdf = 1
listWithImagesExtensions = ["png", "jpg"]
picturesAreInRootFolder = True
nameOfPart = "volume"

unite_pictures_into_pdf(outputPdfName, pathToSavePdfTo, pathToPictures, splitType, numberOfEntitiesInOnePdf, listWithImagesExtensions, picturesAreInRootFolder, nameOfPart)

How to simulate browsing from various locations?

It depends on wether the locatoin is detected by different DNS resolution from different locations, or by IP address that you are browsing from.

If its by DNS, you could just modify your hosts file to point at the server used in europe. Get your friend to ping the address, to see if its different from the one yours resolves to.

To browse from a different IP address:

You can rent a VPS server. You can use putty / SSH to act as a proxy. I use this from time to time to brows from the US using a VPS server I rent in the US.

Having an account on a remote host may or may not be enough. Sadly, my dreamhost account, even though I have ssh access, does not allow proxying.

Find out a Git branch creator


  1. branch was made from master
  2. hasn't been merged to master yet

 git log --format="%ae %an" master..<HERE_COMES_THE_BRANCH_NAME> | tail -1

Toolbar navigation icon never set

Remove this line from activity if you have added

    protected void onPostCreate(Bundle savedInstanceState) {
        // Sync the toggle state after onRestoreInstanceState has occurred.

Then set icon


Perl read line by line

you need to use ++$counter, not $++counter, hence the reason it isn't working..

How to get size in bytes of a CLOB column in Oracle?

After some thinking i came up with this solution:


SUBSTR returns only the first 4000 characters (max string size)

TO_CHAR converts from CLOB to VARCHAR2

LENGTHB returns the length in Bytes used by the string.

Iframe transparent background

I've used this creating an IFrame through Javascript and it worked for me:

// IFrame points to the IFrame element, obviously
IFrame.src = 'about: blank'; = "transparent";
IFrame.frameBorder = "0";

Not sure if it makes any difference, but I set those properties before adding the IFrame to the DOM. After adding it to the DOM, I set its src to the real URL.

What is the Record type in typescript?

A Record lets you create a new type from a Union. The values in the Union are used as attributes of the new type.

For example, say I have a Union like this:

type CatNames = "miffy" | "boris" | "mordred";

Now I want to create an object that contains information about all the cats, I can create a new type using the values in the CatName Union as keys.

type CatList = Record<CatNames, {age: number}>

If I want to satisfy this CatList, I must create an object like this:

const cats:CatList = {
  miffy: { age:99 },
  boris: { age:16 },
  mordred: { age:600 }

You get very strong type safety:

  • If I forget a cat, I get an error.
  • If I add a cat that's not allowed, I get an error.
  • If I later change CatNames, I get an error. This is especially useful because CatNames is likely imported from another file, and likely used in many places.

Real-world React example.

I used this recently to create a Status component. The component would receive a status prop, and then render an icon. I've simplified the code quite a lot here for illustrative purposes

I had a union like this:

type Statuses = "failed" | "complete";

I used this to create an object like this:

const icons: Record<
  { iconType: IconTypes; iconColor: IconColors }
> = {
  failed: {
    iconType: "warning",
    iconColor: "red"
  complete: {
    iconType: "check",
    iconColor: "green"

I could then render by destructuring an element from the object into props, like so:

const Status = ({status}) => <Icon {...icons[status]} />

If the Statuses union is later extended or changed, I know my Status component will fail to compile and I'll get an error that I can fix immediately. This allows me to add additional error states to the app.

Note that the actual app had dozens of error states that were referenced in multiple places, so this type safety was extremely useful.

Add newline to VBA or Visual Basic 6

There are actually two ways of doing this:

  1. st = "Line 1" + vbCrLf + "Line 2"

  2. st = "Line 1" + vbNewLine + "Line 2"

These even work for message boxes (and all other places where strings are used).

jQuery Scroll to bottom of page/iframe


I use this code to scroll the chat when new messages arrive.

Select DISTINCT individual columns in django?

User order by with that field, and then do distinct.

ProductOrder.objects.order_by('category').values_list('category', flat=True).distinct()

Converting a view to Bitmap without displaying it in Android?

here is my solution:

public static Bitmap getBitmapFromView(View view) {
    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(returnedBitmap);
    Drawable bgDrawable =view.getBackground();
    if (bgDrawable!=null) 
    return returnedBitmap;

Enjoy :)

HTML code for INR

Use similar symbol: <del>&#2352;</del> =>

Try &#8377; => ₹

Use an image(bad solution but works): <img src="" width="8" height="10"> =>

Source: Empty rectanglar box is displayed instead of the rupee symbol in HTML

How to click a link whose href has a certain substring in Selenium?

I need to click the link who's href has substring "long" in it. How can I do this?

With the beauty of CSS selectors.

your statement would be...


This means, in english,

Find me any 'a' elements, that have the href attribute, and that attribute contains 'long'

You can find a useful article about formulating your own selectors for automation effectively, as well as a list of all the other equality operators. contains, starts with, etc... You can find that at:

What is an instance variable in Java?

Instance variable is the variable declared inside a class, but outside a method: something like:

class IronMan {

    /** These are all instance variables **/
    public String realName;
    public String[] superPowers;
    public int age;

    /** Getters and setters here **/

Now this IronMan Class can be instantiated in another class to use these variables. Something like:

class Avengers {

    public static void main(String[] a) {
        IronMan ironman = new IronMan();
        ironman.realName = "Tony Stark";
        // or


This is how we use the instance variables. Shameless plug: This example was pulled from this free e-book here here.

What is the difference between =Empty and IsEmpty() in VBA (Excel)?

I believe IsEmpty is just method that takes return value of Cell and checks if its Empty so: IsEmpty(.Cell(i,1)) does ->

return .Cell(i,1) <> Empty

Spark: Add column to dataframe conditionally

My bad, I had missed one part of the question.

Best, cleanest way is to use a UDF. Explanation within the code.

// create some example data...BY DataFrame
// note, third record has an empty string
case class Stuff(a:String,b:Int)
val d= sc.parallelize(Seq( ("a",1),("b",2),
     ("",3) ,("d",4)).map { x => Stuff(x._1,x._2)  }).toDF

// now the good stuff.
import org.apache.spark.sql.functions.udf
// function that returns 0 is string empty 
val func = udf( (s:String) => if(s.isEmpty) 0 else 1 )
// create new dataframe with added column named "notempty"
val r = $"a", $"b", func($"a").as("notempty") )

|  a|  b|notempty|
|  a|  1|    1111|
|  b|  2|    1111|
|   |  3|       0|
|  d|  4|    1111|

Error while retrieving information from the server RPC:s-7:AEC-0 in Google play?

on the BlueStacks emulator worked for me the following solution

Go to ”Settings” -> “Applications” -> “Manage Applications” and select “All

Go to “Google Play Services Framework” and select “Clear Data” & “Clear Cache” to remove all the data.

Go to “Google Play Store” and Select “Clear Data” & “Clear Cache” to remove all the data regarding Google Play Store.

Go to “Settings” -> “Accounts” -> “Google” -> Select “Your Account

Go to “Menu” and Select “Remove Account”.

Now “Restart” your mobile device.

Go to “Menu” and “Add Your Account”.

and try to perform update or download.

Getting date format m-d-Y H:i:s.u from milliseconds

If you want to format a date like JavaScript's (new Date()).toISOString() for some reason, this is how you can do it in PHP:

$now = microtime(true);
gmdate('Y-m-d\TH:i:s', $now).sprintf('.%03dZ',round(($now-floor($now))*1000));

Sample output:


Just to prove that subtracting off the whole number doesn't reduce the accuracy of the decimal portion:

>>> number_format(123.01234567890123456789,25)
=> "123.0123456789012408307826263"
>>> number_format(123.01234567890123456789-123,25)
=> "0.0123456789012408307826263"

PHP did round the decimal places, but it rounded them the same way in both cases.

JTable How to refresh table model after insert delete or update the data.

try this

public void setUpTableData() {
    DefaultTableModel tableModel = (DefaultTableModel) jTable.getModel();

    * additional code.
    ArrayList<Contact> list = new ArrayList<Contact>();
    if (!con.equals(""))
        list = sql.getContactListsByGroup(con);
        list = sql.getContactLists();
    for (int i = 0; i < list.size(); i++) {
        String[] data = new String[7];

        data[0] = list.get(i).getName();
        data[1] = list.get(i).getEmail();
        data[2] = list.get(i).getPhone1();
        data[3] = list.get(i).getPhone2();
        data[4] = list.get(i).getGroup();
        data[5] = list.get(i).getId();

    * additional code.

How to post raw body data with curl?

curl's --data will by default send Content-Type: application/x-www-form-urlencoded in the request header. However, when using Postman's raw body mode, Postman sends Content-Type: text/plain in the request header.

So to achieve the same thing as Postman, specify -H "Content-Type: text/plain" for curl:

curl -X POST -H "Content-Type: text/plain" --data "this is raw data" http://78.41.xx.xx:7778/

Note that if you want to watch the full request sent by Postman, you can enable debugging for packed app. Check this link for all instructions. Then you can inspect the app (right-click in Postman) and view all requests sent from Postman in the network tab :

enter image description here


If the optimizer says they are the same then consider the human factor. I prefer to see NOT EXISTS :)

How do I adb pull ALL files of a folder present in SD Card

Please try with just giving the path from where you want to pull the files I just got the files from sdcard like

adb pull sdcard/

do NOT give * like to broaden the search or to filter out. ex: adb pull sdcard/*.txt --> this is invalid.

just give adb pull sdcard/

How many parameters are too many?

It heavily depends on the environment you're working in. Take for example javascript. In javascript the best way to pass in parameters is using objects with key/value pairs, which in practice means you only have one parameter. In other systems the sweet spot will be at three or four.

In the end, it all boils down to personal taste.

Error: unable to verify the first certificate in nodejs

You can disable certificate checking globally - no matter which package you are using for making requests - like this:

// Disable certificate errors globally
// (ES6 imports (eg typescript))
import * as https from 'https'
https.globalAgent.options.rejectUnauthorized = false


// Disable certificate errors globally
// (vanilla nodejs)
require('https').globalAgent.options.rejectUnauthorized = false

Of course you shouldn't do this - but it's certainly handy for debugging and/or very basic scripting where you absolutely don't care about certificates being validated correctly.

Padding is invalid and cannot be removed?

I encountered this padding error when i would manually edit the encrypted strings in the file (using notepad) because i wanted to test how decryption function will behave if my encrypted content was altered manually.

The solution for me was to place a

            decryption stuff....
             inform decryption will not be carried out.
        end try

Like i said my padding error was because i was manually typing over the decrypted text using notepad. May be my answer may guide you to your solution.

smtpclient " failure sending mail"

Five years later (I hope this developer isn't still waiting for a fix to this..)

I had the same issue, caused by the same error: I was declaring the SmtpClient inside the loop.

The fix is simple - declare it once, outside the loop...

MailAddress mail = null;
SmtpClient client = new SmtpClient();
client.Port = 25;
client.EnableSsl = false;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = true;
client.Host = smtpAddress;       //  Enter your company's email server here!

for(int i = 0; i < number ; i++)
    mail = new MailMessage(iMail.from,;
    mail.Subject = iMail.sub;
    mail.Body = iMail.body;
    mail.IsBodyHtml = true;
    mail.Priority = MailPriority.Normal;
    mail.Sender = from;

Remove trailing newline from the elements of a string list

my_list = ['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']
print([l.strip() for l in my_list])


['this', 'is', 'a', 'list', 'of', 'words']

Spring cannot find bean xml configuration file when it does exist

Beans.xml or file.XML is not placed under proper path. You should add the XML file under the resource folder, if you have a Maven project. src -> main -> java -> resources

What is difference between arm64 and armhf?

Update: Yes, I understand that this answer does not explain the difference between arm64 and armhf. There is a great answer that does explain that on this page. This answer was intended to help set the asker on the right path, as they clearly had a misunderstanding about the capabilities of the Raspberry Pi at the time of asking.

Where are you seeing that the architecture is armhf? On my Raspberry Pi 3, I get:

$ uname -a

Anyway, armv7 indicates that the system architecture is 32-bit. The first ARM architecture offering 64-bit support is armv8. See this table for reference.

You are correct that the CPU in the Raspberry Pi 3 is 64-bit, but the Raspbian OS has not yet been updated for a 64-bit device. 32-bit software can run on a 64-bit system (but not vice versa). This is why you're not seeing the architecture reported as 64-bit.

You can follow the GitHub issue for 64-bit support here, if you're interested.

How to refresh an IFrame using Javascript?

Got this from here

var f = document.getElementById('iframe1');
f.src = f.src;

c# regex matches example

    public void match2()
        string input = "%download%#893434";
        Regex word = new Regex(@"\d+");
        Match m = word.Match(input);

Git - How to fix "corrupted" interactive rebase?

I got stuck in this. I created the head-name file, and then I ran into another error saying it couldn't find the onto file, so I created that file. Then I got another error saying could not read '.git/rebase-apply/onto': No such file or directory.

So I looked at the git documentation for rebasing and found another command:

git rebase --quit

This set me back on my branch with no changes, and I could start my rebase over again, good as new.

Expand a random range from 1–5 to 1–7

solution in php

function random_5(){
    return rand(1,5);

function random_7(){
 $total = 0;

        $total += random_5();

    return ($total%7)+1; 

echo random_7();

Loop through JSON object List

Be careful, d is the list.

for (var i = 0; i < result.d.length; i++) { 

SecurityError: The operation is insecure - window.history.pushState()

I solved it by switching tohttp protocol from the file protocol.

  • you can use "live-server" extension in VS code,
  • or, on node, use live-server [dirPath]

Bootstrap: add margin/padding space between columns

You may use the padding and margin shorthand Bootstrap 4 classes as follows:

For extra small devices i.e. xs


For other devices/viewports (small, medium, large and extra large)



property = m for margin and p for padding

Following are sides shorthand meanings:

l = defines the left-margin or left-padding
r = defines the right-margin or right-padding
t = defines the top-margin or top-padding
b = defines the bottom-margin or right-padding
x = For setting left and right padding and margins by the single call
y = For setting top and bottom margins
blank = margin and padding for all sides

The breakpoint = sm, md, lg, and xl.

Combining all the above, the left padding complete code can be (for example):

For left padding in extra small devices


or for medium to extra large


How to make Bootstrap 4 cards the same height in card-columns?

I came across this problem, most people use jQuery... Here was my solution. "Do not mind, I am just a beginner in this..."

.cards-collection {
    .card-item { 
        width: 100%;
        margin: 20px 20px;
        padding:0 ;
        .card {
            border-radius: 10px;
                button {
                    border: inherit;

If any card item height is e.g. 400px (based on it's contents), because the default for flex-align is stretch, then .card-item (child of row or card-collection class) will be stretched. making the height of the card to be 100% of the parent will occupy this full height.

I hope I was correct. Am I?

How can I import a large (14 GB) MySQL dump file into a new MySQL database?

I have made a PHP script which is designed to import large database dumps which have been generated by phpmyadmin or mysql dump (from cpanel) . It's called PETMI and you can download it here [project page] [gitlab page].

It works by splitting an. sql file into smaller files called a split and processing each split one at a time. Splits which fail to process can be processed manually by the user in phpmyadmin. This can be easily programmed as in sql dumps, each command is on a new line. Some things in sql dumps work in phpmyadmin imports but not in mysqli_query so those lines have been stripped from the splits.

It has been tested with a 1GB database. It has to be uploaded to an existing website. PETMI is open source and the sample code can be seen on Gitlab.

A moderator asked me to provide some sample code. I'm on a phone so excuse the formatting.

Here is the code that creates the splits.

                 //gets the config page
                  if (isset($_POST['register']) && $_POST['register'])
                 echo " <img src=\"loading.gif\">";
        $folder = "split/";
        include ("config.php");
        $fh = fopen("importme.sql", 'a') or die("can't open file");
        $stringData = "-- --------------------------------------------------------";
        fwrite($fh, $stringData);
        $file2 = fopen("importme.sql","r");
        //echo "<br><textarea class=\"mediumtext\" style=\"width: 500px; height: 200px;\">";
        $danumber = "1";
        while(! feof($file2)){
            //echo fgets($file2)."<!-- <br /><hr color=\"red\" size=\"15\"> -->"; 
            $oneline = fgets($file2); //this is fgets($file2) but formatted nicely
            //echo "<br>$oneline";
            $findme1  = '-- --------------------------------------------------------';
            $pos1 = strpos($oneline, $findme1);
            $findme2  = '-- Table structure for';
            $pos2 = strpos($oneline, $findme2);
            $findme3  = '-- Dumping data for';
            $pos3 = strpos($oneline, $findme3);
            $findme4  = '-- Indexes for dumped tables';
            $pos4 = strpos($oneline, $findme4);
            $findme5  = '-- AUTO_INCREMENT for dumped tables';
            $pos5 = strpos($oneline, $findme5);
            if ($pos1 === false && $pos2 === false && $pos3 === false && $pos4 === false && $pos5 === false) {

                // setcookie("filenumber",$i);
                // if ($danumber2 == ""){$danumber2 = "0";} else { $danumber2 = $danumber2 +1;}                 
                $ourFileName = "split/sql-split-$danumber.sql";
                // echo "writing danumber is $danumber";
                $ourFileHandle = fopen($ourFileName, 'a') or die("can't edit file. chmod directory to 777");

                $stringData = $oneline;
                $stringData = preg_replace("/\/[*][!\d\sA-Za-z@_='+:,]*[*][\/][;]/", "", $stringData);
                $stringData = preg_replace("/\/[*][!]*[\d A-Za-z`]*[*]\/[;]/", "", $stringData);
                $stringData = preg_replace("/DROP TABLE IF EXISTS `[a-zA-Z]*`;/", "", $stringData);
                $stringData = preg_replace("/LOCK TABLES `[a-zA-Z` ;]*/", "", $stringData);
                $stringData = preg_replace("/UNLOCK TABLES;/", "", $stringData);

                fwrite($ourFileHandle, $stringData);
            } else {
                    //write new file;
                    if ($danumber == ""){$danumber = "1";} else { $danumber = $danumber +1;}
                    $ourFileName = "split/sql-split-$danumber.sql"; 
                    //echo "$ourFileName has been written with the contents above.\n";
                    $ourFileName = "split/sql-split-$danumber.sql";
                    $ourFileHandle = fopen($ourFileName, 'a') or die("can't edit file. chmod directory to 777");
                    $stringData = "$oneline";
                    fwrite($ourFileHandle, $stringData);
        //echo "</textarea>";

Here is the code that imports the split

// allows you to use cookies
include ("config.php");
//gets the config page
if (isset($_POST['register']))
echo "<div id**strong text**=\"sel1\"><img src=\"loading.gif\"></div>";

// the above line checks to see if the html form has been submitted
$dbname = $accesshost;
$dbhost = $username;
$dbuser = $password;
$dbpasswd = $database;
$table_prefix = $dbprefix;
//the above lines set variables with the user submitted information
    //none were left blank!  We continue...

//echo "$importme";

echo "<hr>";

$importme = "$_GET[file]";
$importme = file_get_contents($importme);
//echo "<b>$importme</b><br><br>";
$sql = $importme;
$findme1  = '-- Indexes for dumped tables';
$pos1 = strpos($importme, $findme1);
$findme2 = '-- AUTO_INCREMENT for dumped tables';
$pos2 = strpos($importme, $findme2);

$dbhost = '';

if($pos1 !== false){
    $splitted = explode("-- Indexes for table", $importme);
    // print_r($splitted);
        $sql = $splitted[$i];
        $sql = preg_replace("/[`][a-z`\s]*[-]{2}/", "", $sql);
        // echo "<b>$sql</b><hr>";
        if($table_prefix !== 'phpbb_') $sql = preg_replace('/phpbb_/', $table_prefix, $sql);
        $res = mysql_query($sql);
    if(!$res) { echo '<b>error in query </b>', mysql_error(), '<br /><br>Try importing the split .sql file in phpmyadmin under the SQL tab.'; /* $i = $i +1; */ } else {
    echo ("<meta http-equiv=\"Refresh\" content=\"0; URL=restore.php?page=done&file=$filename\"/>Thank You! You will be redirected");
} elseif($pos2 !== false){
    $splitted = explode("-- AUTO_INCREMENT for table", $importme);
    // print_r($splitted);
        $sql = $splitted[$i];
        $sql = preg_replace("/[`][a-z`\s]*[-]{2}/", "", $sql);
        // echo "<b>$sql</b><hr>";
        if($table_prefix !== 'phpbb_') $sql = preg_replace('/phpbb_/', $table_prefix, $sql);
        $res = mysql_query($sql);
    if(!$res) { echo '<b>error in query </b>', mysql_error(), '<br /><br>Try importing the split .sql file in phpmyadmin under the SQL tab.'; /* $i = $i +1; */ } else {
    echo ("<meta http-equiv=\"Refresh\" content=\"0; URL=restore.php?page=done&file=$filename\"/>Thank You! You will be redirected");
} else {
    if($table_prefix !== 'phpbb_') $sql = preg_replace('/phpbb_/', $table_prefix, $sql);
    $res = mysql_query($sql);
    if(!$res) { echo '<b>error in query </b>', mysql_error(), '<br /><br>Try importing the split .sql file in phpmyadmin under the SQL tab.'; /* $i = $i +1; */ } else {
    echo ("<meta http-equiv=\"Refresh\" content=\"0; URL=restore.php?page=done&file=$filename\"/>Thank You! You will be redirected");


//echo 'done (', count($sql), ' queries).';



Compare two different files line by line in python

If order is preserved between files you might also prefer difflib. Although Rob?'s result is the bona-fide standard for intersections you might actually be looking for a rough diff-like:

from difflib import Differ

with open('cfg1.txt') as f1, open('cfg2.txt') as f2:
    differ = Differ()

    for line in, f2.readlines()):
        if line.startswith(" "):
            print(line[2:], end="")

That said, this has a different behaviour to what you asked for (order is important) even though in this instance the same output is produced.

Auto populate columns in one sheet from another sheet

Use the 'EntireColumn' property, that's what it is there for. C# snippet, but should give you a good indication of how to do this:

string rangeQuery = "A1:A1";

Range range = workSheet.get_Range(rangeQuery, Type.Missing);

range = range.EntireColumn;

How to process images of a video, frame by frame, in video streaming using OpenCV and Python

According to the latest updates for OpenCV 3.0 and higher, you need to change the Property Identifiers as follows in the code by Mehran:



and same applies to cv2.CAP_PROP_POS_FRAME_COUNT.

Hope it helps.

R Error in x$ed : $ operator is invalid for atomic vectors

The reason you are getting this error is that you have a vector.

If you want to use the $ operator, you simply need to convert it to a data.frame. But since you only have one row in this particular case, you would also need to transpose it; otherwise bob and ed will become your row names instead of your column names which is what I think you want.

x <- c(1, 2)
names(x) <- c("bob", "ed")
x <-
[1] 2

Disable vertical sync for glxgears

For Intel graphics and AMD/ATI opensource graphics drivers

Find the "Device" section of /etc/X11/xorg.conf which contains one of the following directives:

  • Driver "intel"
  • Driver "radeon"
  • Driver "fglrx"

And add the following line to that section:

Option     "SwapbuffersWait"       "false"

And run your application with vblank_mode environment variable set to 0:

$ vblank_mode=0 glxgears

For Nvidia graphics with the proprietary Nvidia driver

$ echo "0/SyncToVBlank=0" >> ~/.nvidia-settings-rc

The same change can be made in the nvidia-settings GUI by unchecking the option at X Screen 0 / OpenGL Settings / Sync to VBlank. Or, if you'd like to just test the setting without modifying your ~/.nvidia-settings-rc file you can do something like:

$ nvidia-settings --load-config-only --assign="SyncToVBlank=0"  # disable vertical sync
$ glxgears  # test it out
$ nvidia-settings --load-config-only  # restore your original vertical sync setting

How do I delete an item or object from an array using ng-click?

Building on the accepted answer, this will work with ngRepeat, filterand handle expections better:


vm.remove = function(item, array) {
  var index = array.indexOf(item);
    array.splice(index, 1);



Sorting Python list based on the length of the string

def lensort(list_1):
for i in list_1:
list_2.sort(key = lambda x : x[1])
for i in list_2:
return list_3

This works for me!

how to check for null with a ng-if values in a view with angularjs?

You should check for !test, here is a fiddle showing that.

<span ng-if="!test">null</span>

Benefits of EBS vs. instance-store (and vice-versa)

I'm just starting to use EC2 myself so not an expert, but Amazon's own documentation says:

we recommend that you use the local instance store for temporary data and, for data requiring a higher level of durability, we recommend using Amazon EBS volumes or backing up the data to Amazon S3.

Emphasis mine.

I do more data analysis than web hosting, so persistence doesn't matter as much to me as it might for a web site. Given the distinction made by Amazon itself, I wouldn't assume that EBS is right for everyone.

I'll try to remember to weigh in again after I've used both.

How to split a string in two and store it in a field

I would suggest the following:

String[] parsedInput = str.split("\n"); String firstName = parsedInput[0].split(": ")[1]; String lastName = parsedInput[1].split(": ")[1]; myMap.put(firstName,lastName); 

How to use regex in String.contains() method in Java

As of Java 11 one can use Pattern#asMatchPredicate which returns Predicate<String>.

String string = "stores%store%product";
String regex = "stores.*store.*product.*";
Predicate<String> matchesRegex = Pattern.compile(regex).asMatchPredicate();

boolean match = matchesRegex.test(string);                   // true

The method enables chaining with other String predicates, which is the main advantage of this method as long as the Predicate offers and, or and negate methods.

String string = "stores$store$product";
String regex = "stores.*store.*product.*";

Predicate<String> matchesRegex = Pattern.compile(regex).asMatchPredicate();
Predicate<String> hasLength = s -> s.length() > 20;

boolean match = hasLength.and(matchesRegex).test(string);    // false

How to find out what character key is pressed?

"Clear" JavaScript:

function myKeyPress(e){
  var keynum;

  if(window.event) { // IE                  
    keynum = e.keyCode;
  } else if(e.which){ // Netscape/Firefox/Opera                 
    keynum = e.which;

<input type="text" onkeypress="return myKeyPress(event)" />


<script src=""></script>

How to copy sheets to another workbook using vba?

Assuming all your macros are in modules, maybe this link will help. After copying the workbook, just iterate over each module and delete it

Conversion of Char to Binary in C

Your code is very vague and not understandable, but I can provide you with an alternative.

First of all, if you want temp to go through the whole string, you can do something like this:

char *temp;
for (temp = your_string; *temp; ++temp)
    /* do something with *temp */

The term *temp as the for condition simply checks whether you have reached the end of the string or not. If you have, *temp will be '\0' (NUL) and the for ends.

Now, inside the for, you want to find the bits that compose *temp. Let's say we print the bits:

for (as above)
    int bit_index;
    for (bit_index = 7; bit_index >= 0; --bit_index)
        int bit = *temp >> bit_index & 1;
        printf("%d", bit);

To make it a bit more generic, that is to convert any type to bits, you can change the bit_index = 7 to bit_index = sizeof(*temp)*8-1

Alter MySQL table to add comments on columns

Script for all fields on database:

        '` CHANGE `',
        '` `',
        '` ',
        ' ',
        IF(is_nullable = 'YES', '' , 'NOT NULL '),
        IF(column_default IS NOT NULL, concat('DEFAULT ', IF(column_default IN ('CURRENT_TIMESTAMP', 'CURRENT_TIMESTAMP()', 'NULL', 'b\'0\'', 'b\'1\''), column_default, CONCAT('\'',column_default,'\'') ), ' '), ''),
        IF(column_default IS NULL AND is_nullable = 'YES' AND column_key = '' AND column_type = 'timestamp','NULL ', ''),
        IF(column_default IS NULL AND is_nullable = 'YES' AND column_key = '','DEFAULT NULL ', ''),
        ' COMMENT \'',
        '\' ;') as script
    table_schema = 'my_database_name'
ORDER BY table_name , column_name
  1. Export all to a CSV
  2. Open it on your favorite csv editor

Note: You can improve to only one table if you prefer

The solution given by @Rufinus is great but if you have auto increments it will break it.

jQuery selector to get form by name

$('form[name="frmSave"]') is correct. You mentioned you thought this would get all children with the name frmsave inside the form; this would only happen if there was a space or other combinator between the form and the selector, eg: $('form [name="frmSave"]');

$('form[name="frmSave"]') literally means find all forms with the name frmSave, because there is no combinator involved.

Date format in dd/MM/yyyy hh:mm:ss

This can be done as follows :

select CONVERT(VARCHAR(10), GETDATE(), 103) + ' '  + convert(VARCHAR(8), GETDATE(), 14)

Hope it helps

Where can I find the API KEY for Firebase Cloud Messaging?

STEP 1: Go to Firebase Console

STEP 2: Select your Project

STEP 3: Click on Settings icon and select Project Settings

Select Project Setting


enter image description here

How to override equals method in Java

Since I'm guessing age is of type int:

public boolean equals(Object other){
    boolean result;
    if((other == null) || (getClass() != other.getClass())){
        result = false;
    } // end if
        People otherPeople = (People)other;
        result = name.equals( &&  age == otherPeople.age;
    } // end else

    return result;
} // end equals

How to set a text box for inputing password in winforms?

private void cbShowHide_CheckedChanged(object sender, EventArgs e)
    if (cbShowHide.Checked)
        txtPin.UseSystemPasswordChar = PasswordPropertyTextAttribute.No.Password;
        //Hides Textbox password
        txtPin.UseSystemPasswordChar = PasswordPropertyTextAttribute.Yes.Password;

Copy this code to show and hide your textbox using a checkbox

How to export collection to CSV in MongoDB?

For all those who are stuck with an error.

Let me give you guys a solution with a brief explanation of the same:-

command to connect:-

mongoexport --host your_host --port your_port -u your_username -p your_password --db your_db --collection your_collection --type=csv --out file_name.csv --fields all_the_fields --authenticationDatabase admin

--host --> host of Mongo server

--port --> port of Mongo server

-u --> username

-p --> password

--db --> db from which you want to export

--collection --> collection you want to export

--type --> type of export in my case CSV

--out --> file name where you want to export

--fields --> all the fields you want to export (don't give spaces in between two field name in between commas in case of CSV)

--authenticationDatabase --> database where all your user information is stored

How do I open a new fragment from another fragment?

Well my problem was that i used the code from the answer, which is checked as a solution here, but after the replacement was executed, the first layer was still visible and functionating under just opened fragment. My solution was simmple, i added


the CourseListFragment is a class file for the fragment i tried to close. (, but for specific section (navigation drawer fragment), if it makes more sense to you) so my code looks like this now :

LecturesFragment nextFrag= new LecturesFragment();

                            .replace(((ViewGroup)getView().getParent()).getId(), nextFrag, "findThisFragment")

And it works like a charm for me.

C#: Converting byte array to string and printing out to console

 byte[] bytes = { 1,2,3,4 };

 string stringByte= BitConverter.ToString(bytes);


Javascript negative number

Instead of writing a function to do this check, you should just be able to use this expression:

(number < 0)

Javascript will evaluate this expression by first trying to convert the left hand side to a number value before checking if it's less than zero, which seems to be what you wanted.

Specifications and details

The behavior for x < y is specified in §11.8.1 The Less-than Operator (<), which uses §11.8.5 The Abstract Relational Comparison Algorithm.

The situation is a lot different if both x and y are strings, but since the right hand side is already a number in (number < 0), the comparison will attempt to convert the left hand side to a number to be compared numerically. If the left hand side can not be converted to a number, the result is false.

Do note that this may give different results when compared to your regex-based approach, but depending on what is it that you're trying to do, it may end up doing the right thing anyway.

  • "-0" < 0 is false, which is consistent with the fact that -0 < 0 is also false (see: signed zero).
  • "-Infinity" < 0 is true (infinity is acknowledged)
  • "-1e0" < 0 is true (scientific notation literals are accepted)
  • "-0x1" < 0 is true (hexadecimal literals are accepted)
  • " -1 " < 0 is true (some forms of whitespaces are allowed)

For each of the above example, the regex method would evaluate to the contrary (true instead of false and vice versa).


See also

Appendix 1: Conditional operator ?:

It should also be said that statements of this form:

if (someCondition) {
   return valueForTrue;
} else {
   return valueForFalse;

can be refactored to use the ternary/conditional ?: operator (§11.12) to simply:

return (someCondition) ? valueForTrue : valueForFalse;

Idiomatic usage of ?: can make the code more concise and readable.

Related questions

Appendix 2: Type conversion functions

Javascript has functions that you can call to perform various type conversions.

Something like the following:

if (someVariable) {
   return true;
} else {
   return false;

Can be refactored using the ?: operator to:

return (someVariable ? true : false);

But you can also further simplify this to:

return Boolean(someVariable);

This calls Boolean as a function (§15.16.1) to perform the desired type conversion. You can similarly call Number as a function (§15.17.1) to perform a conversion to number.

Related questions


The ON UPDATE and ON DELETE specify which action will execute when a row in the parent table is updated and deleted. The following are permitted actions : NO ACTION, CASCADE, SET NULL, and SET DEFAULT.

Delete actions of rows in the parent table

If you delete one or more rows in the parent table, you can set one of the following actions:

  • ON DELETE NO ACTION: SQL Server raises an error and rolls back the delete action on the row in the parent table.
  • ON DELETE CASCADE: SQL Server deletes the rows in the child table that is corresponding to the row deleted from the parent table.
  • ON DELETE SET NULL: SQL Server sets the rows in the child table to NULL if the corresponding rows in the parent table are deleted. To execute this action, the foreign key columns must be nullable.
  • ON DELETE SET DEFAULT: SQL Server sets the rows in the child table to their default values if the corresponding rows in the parent table are deleted. To execute this action, the foreign key columns must have default definitions. Note that a nullable column has a default value of NULL if no default value specified. By default, SQL Server appliesON DELETE NO ACTION if you don’t explicitly specify any action.

Update action of rows in the parent table

If you update one or more rows in the parent table, you can set one of the following actions:

  • ON UPDATE NO ACTION: SQL Server raises an error and rolls back the update action on the row in the parent table.
  • ON UPDATE CASCADE: SQL Server updates the corresponding rows in the child table when the rows in the parent table are updated.
  • ON UPDATE SET NULL: SQL Server sets the rows in the child table to NULL when the corresponding row in the parent table is updated. Note that the foreign key columns must be nullable for this action to execute.
  • ON UPDATE SET DEFAULT: SQL Server sets the default values for the rows in the child table that have the corresponding rows in the parent table updated.
FOREIGN KEY (foreign_key_columns)
    REFERENCES parent_table(parent_key_columns)
    ON UPDATE <action> 
    ON DELETE <action>;

See the reference tutorial.

Changing variable names with Python for loops

Definitely should use a dict using the "group" + str(i) key as described in the accepted solution but I wanted to share a solution using exec. Its a way to parse strings into commands & execute them dynamically. It would allow to create these scalar variable names as per your requirement instead of using a dict. This might help in regards what not to do, and just because you can doesn't mean you should. Its a good solution only if using scalar variables is a hard requirement:

l = locals()
for i in xrange(3):
    exec("group" + str(i) + "= self.getGroup(selected, header + i)")

Another example where this could work using a Django model example. The exec alternative solution is commented out and the better way of handling such a case using the dict attribute makes more sense:

Class A(models.Model):


    def __getitem__(self, item):  # a.__getitem__('id')
        #exec("attrb = self." + item)
        #return attrb
        return self.__dict__[item]

It might make more sense to extend from a dictionary in the first place to get setattr and getattr functions.

A situation which involves parsing, for example generating & executing python commands dynamically, exec is what you want :) More on exec here.

What does %~dp0 mean, and how does it work?

Great example from Strawberry Perl's portable shell launcher:

set drive=%~dp0
set drivep=%drive%
if #%drive:~-1%# == #\# set drivep=%drive:~0,-1%

set PATH=%drivep%\perl\site\bin;%drivep%\perl\bin;%drivep%\c\bin;%PATH%

not sure what the negative 1's doing there myself, but it works a treat!

Can I underline text in an Android layout?

I used this xml drawable to create a bottom-border and applied the drawable as the background to my textview

<layer-list xmlns:android="">
        <shape android:shape="rectangle" >
            <solid android:color="@android:color/transparent" />

    <item android:top="-5dp" android:right="-5dp" android:left="-5dp">
            <solid android:color="@android:color/transparent" />
                    android:color="@color/pure_white" />

Controlling fps with requestAnimationFrame?

I suggest wrapping your call to requestAnimationFrame in a setTimeout:

const fps = 25;
function animate() {
  // perform some animation task here

  setTimeout(() => {
  }, 1000 / fps);

You need to call requestAnimationFrame from within setTimeout, rather than the other way around, because requestAnimationFrame schedules your function to run right before the next repaint, and if you delay your update further using setTimeout you will have missed that time window. However, doing the reverse is sound, since you’re simply waiting a period of time before making the request.

Need to navigate to a folder in command prompt

When I open a "DOS" command prompt, I use a batch file which sets all of the options I need and adds my old-time dos utilities to the path too.

@set path=%path%;c:\utils
@doskey cd=cd/d $*
@cd \wip

The doskey line sets the CD command so that it will do both drive and folder simultaneously. If this doesn't work, it is possibly because of the version of windows that you're running.

jQuery - Follow the cursor with a DIV

This works for me. Has a nice delayed action going on.

var $mouseX = 0, $mouseY = 0;
var $xp = 0, $yp =0;

    $mouseX = e.pageX;
    $mouseY = e.pageY;    

var $loop = setInterval(function(){
// change 12 to alter damping higher is slower
$xp += (($mouseX - $xp)/12);
$yp += (($mouseY - $yp)/12);
$("#moving_div").css({left:$xp +'px', top:$yp +'px'});  
}, 30);

Nice and simples

How to use order by with union all in sql?

            SELECT * FROM TABLE_A 
            UNION ALL 
            SELECT * FROM TABLE_B
        ) dum
-- ORDER BY .....

but if you want to have all records from Table_A on the top of the result list, the you can add user define value which you can use for ordering,

            SELECT *, 1 sortby FROM TABLE_A 
            UNION ALL 
            SELECT *, 2 sortby FROM TABLE_B
        ) dum
ORDER   BY sortby 

PowerShell To Set Folder Permissions

Specifying inheritance in the FileSystemAccessRule() constructor fixes this, as demonstrated by the modified code below (notice the two new constuctor parameters inserted between "FullControl" and "Allow").

$Acl = Get-Acl "\\R9N2WRN\Share"

$Ar = New-Object System.Security.AccessControl.FileSystemAccessRule("user", "FullControl", "ContainerInherit,ObjectInherit", "None", "Allow")

Set-Acl "\\R9N2WRN\Share" $Acl

According to this topic

"when you create a FileSystemAccessRule the way you have, the InheritanceFlags property is set to None. In the GUI, this corresponds to an ACE with the Apply To box set to "This Folder Only", and that type of entry has to be viewed through the Advanced settings."

I have tested the modification and it works, but of course credit is due to the MVP posting the answer in that topic.

Linking to a specific part of a web page

Create a "jump link" using the following format:

Where anchor is the id of the element you wish to link to on that page. Use browser development tools / view source to find the id of the element you wish to link to.

If the element doesnt have an id and you dont control that site then you cant do it.

How to assign bean's property an Enum value in Spring config file?

Have you tried just "TYPE1"? I suppose Spring uses reflection to determine the type of "type" anyway, so the fully qualified name is redundant. Spring generally doesn't subscribe to redundancy!

Changing the color of an hr element

Tested in Firefox, Opera, Internet Explorer, Chrome and Safari.

hr {
    border-top: 1px solid red;

See the Fiddle.

Python:Efficient way to check if dictionary is empty or not

I just wanted to know if the dictionary i was going to try to pull data from had data in it in the first place, this seems to be simplest way.

d = {}


#should return

d = {'hello':'world'}


#should return

How to add a string to a string[] array? There's no .Add function

I would not use an array in this case. Instead I would use a StringCollection.

using System.Collections.Specialized;

private StringCollection ColeccionDeCortes(string Path)   

    DirectoryInfo X = new DirectoryInfo(Path);

    FileInfo[] listaDeArchivos = X.GetFiles();
    StringCollection Coleccion = new StringCollection();

    foreach (FileInfo FI in listaDeArchivos)
        Coleccion.Add( FI.Name );
    return Coleccion;

How is Docker different from a virtual machine?

In relation to:-

"Why is deploying software to a docker image easier than simply deploying to a consistent production environment ?"

Most software is deployed to many environments, typically a minimum of three of the following:

  1. Individual developer PC(s)
  2. Shared developer environment
  3. Individual tester PC(s)
  4. Shared test environment
  5. QA environment
  6. UAT environment
  7. Load / performance testing
  8. Live staging
  9. Production
  10. Archive

There are also the following factors to consider:

  • Developers, and indeed testers, will all have either subtlely or vastly different PC configurations, by the very nature of the job
  • Developers can often develop on PCs beyond the control of corporate or business standardisation rules (e.g. freelancers who develop on their own machines (often remotely) or contributors to open source projects who are not 'employed' or 'contracted' to configure their PCs a certain way)
  • Some environments will consist of a fixed number of multiple machines in a load balanced configuration
  • Many production environments will have cloud-based servers dynamically (or 'elastically') created and destroyed depending on traffic levels

As you can see the extrapolated total number of servers for an organisation is rarely in single figures, is very often in triple figures and can easily be significantly higher still.

This all means that creating consistent environments in the first place is hard enough just because of sheer volume (even in a green field scenario), but keeping them consistent is all but impossible given the high number of servers, addition of new servers (dynamically or manually), automatic updates from o/s vendors, anti-virus vendors, browser vendors and the like, manual software installs or configuration changes performed by developers or server technicians, etc. Let me repeat that - it's virtually (no pun intended) impossible to keep environments consistent (okay, for the purist, it can be done, but it involves a huge amount of time, effort and discipline, which is precisely why VMs and containers (e.g. Docker) were devised in the first place).

So think of your question more like this "Given the extreme difficulty of keeping all environments consistent, is it easier to deploying software to a docker image, even when taking the learning curve into account ?". I think you'll find the answer will invariably be "yes" - but there's only one way to find out, post this new question on Stack Overflow.

MySQL, Concatenate two columns

You can use the CONCAT function like this:



To get that result you can try this:

SET @rn := 0;

SELECT CONCAT(`SUBJECT`,'-',`YEAR`,'-',LPAD(@rn := @rn+1,3,'0'))
FROM `table`

How to redirect to another page in node.js

Ok, I'll try to help you using one my examples. First of all, you need to know I am using express for my application directory structure and for creating files like app.js in an automatically way. My login.html looks like:

<div class="form">
<h2>Login information</h2>
<form action="/login" method = "post">
  <input type="text" placeholder="E-Mail" name="email" required/>
  <input type="password" placeholder="Password" name="password" required/>

The important thing here is action="/login". This is the path I use in my index.js (for navigating between the views) which look like this:'/login', passport.authenticate('login', {
    successRedirect : '/home', 
    failureRedirect : '/login', 
    failureFlash : true

app.get('/home', function(request, response) {

This allows me to redirect to another page after a succesful login. There is a helpful tutorial you could check out for redirecting between pages:

To read a statement like <%= %> let's have a look at a simple profile.html which has the following structure:

<div id = "profile">
            <label id = "usernameLabel">Username:</label>
            <input type = "text" id="usernameText" value = "<%= user.user.username %>" />

To get the the attributes of the user variable, you have to initialize a user variable in your routing.js (called index.js in my case). This looks like

app.get('/profile', auth, function(request, response) {
    response.render('pages/profile', {
        user : request.user

I am using mongoose for my object model:

var mongoose = require('mongoose');
var bcrypt   = require('bcrypt-nodejs');
var role     = require('./role');

var userSchema = mongoose.Schema({
    user             : {
        username     : String,
        email        : String,
        password     : String

Ask me anytime for further questions... Best regards, Nazar

CSV file written with Python has blank lines between each row

I'm writing this answer w.r.t. to python 3, as I've initially got the same problem.

I was supposed to get data from arduino using PySerial, and write them in a .csv file. Each reading in my case ended with '\r\n', so newline was always separating each line.

In my case, newline='' option didn't work. Because it showed some error like :

with open('op.csv', 'a',newline=' ') as csv_file:

ValueError: illegal newline value: ''

So it seemed that they don't accept omission of newline here.

Seeing one of the answers here only, I mentioned line terminator in the writer object, like,

writer = csv.writer(csv_file, delimiter=' ',lineterminator='\r')

and that worked for me for skipping the extra newlines.

Unsafe JavaScript attempt to access frame with URL

I was getting the same error message when I tried to change the domain for iframe.src.

For me, the answer was to change the iframe.src to a url on the same domain, but which was actually an html re-direct page to the desired domain. The other domain then showed up in my iframe without any errors.

Worked like a charm.:)

The calling thread must be STA, because many UI components require this

I suspect that you are getting a callback to a UI component from a background thread. I recommend that you make that call using a BackgroundWorker as this is UI thread aware.

For the BackgroundWorker, the main program should be marked as [STAThread].

Python: IndexError: list index out of range

I think you mean to put the rolling of the random a,b,c, etc within the loop:

a = None # initialise
while not (a in winning_numbers):
    # keep rolling an a until you get one not in winning_numbers
    a = random.randint(1,30)

Otherwise, a will be generated just once, and if it is in winning_numbers already, it won't be added. Since the generation of a is outside the while (in your code), if a is already in winning_numbers then too bad, it won't be re-rolled, and you'll have one less winning number.

That could be what causes your error in if guess[i] == winning_numbers[i]. (Your winning_numbers isn't always of length 5).

How to remove button shadow (android)

Instead of a Button, you can use a TextView and add a click listener in the java code.


in the activity layout xml:

    android:textAllCaps="true" />

in the activity java file:

TextView btnTextView = (TextView) findViewById(;
btnTextView.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // handler code

Using print statements only to debug

The logging module has everything you could want. It may seem excessive at first, but only use the parts you need. I'd recommend using logging.basicConfig to toggle the logging level to stderr and the simple log methods, debug, info, warning, error and critical.

import logging, sys
logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)
logging.debug('A debug message!')'We processed %d records', len(processed_records))

Push an associative item into an array in JavaScript

To make something like associative array in JavaScript you have to use objects. ?

var obj = {}; // {} will create an object
var name = "name";
var val = 2;
obj[name] = val;


Batch files: List all files in a directory with relative paths

Of course, you may write a recursive algorithm in Batch that gives you exact control of what you do in every nested subdirectory:

@echo off
set mypath=
call :treeProcess
goto :eof

for %%f in (*.txt) do echo %mypath%%%f
for /D %%d in (*) do (
    set mypath=%mypath%%%d\
    cd %%d
    call :treeProcess
    cd ..
exit /b

How to insert data using wpdb

You have to check your quotes properly,

$sql = $wpdb->prepare(
    "INSERT INTO `wp_submitted_form`      
 values ($name, $email, $phone, $country, $course, $message, $datesent)");

OR you can use like,

$sql = "INSERT INTO `wp_submitted_form`
   values ($name, $email, $phone, $country, $course, $message, $datesent)";



CSS how to make scrollable list

As per your question vertical listing have a scrollbar effect.


nav ul{height:200px; width:18%;}_x000D_
nav ul{overflow:hidden; overflow-y:scroll;}
<!DOCTYPE html>_x000D_
        <meta charset="utf-8">_x000D_
        <title>JS Bin</title>_x000D_
        <header>header area</header>_x000D_
                <li>Link 1</li>_x000D_
                <li>Link 2</li>_x000D_
                <li>Link 3</li>_x000D_
                <li>Link 4</li>_x000D_
                <li>Link 5</li>_x000D_
                <li>Link 6</li> _x000D_
                <li>Link 7</li> _x000D_
                <li>Link 8</li>_x000D_
                <li>Link 9</li>_x000D_
                <li>Link 10</li>_x000D_
                <li>Link 11</li>_x000D_
                <li>Link 13</li>_x000D_
                <li>Link 13</li>_x000D_
        <footer>footer area</footer>_x000D_

Add a column in a table in HIVE QL

You cannot add a column with a default value in Hive. You have the right syntax for adding the column ALTER TABLE test1 ADD COLUMNS (access_count1 int);, you just need to get rid of default sum(max_count). No changes to that files backing your table will happen as a result of adding the column. Hive handles the "missing" data by interpreting NULL as the value for every cell in that column.

So now your have the problem of needing to populate the column. Unfortunately in Hive you essentially need to rewrite the whole table, this time with the column populated. It may be easier to rerun your original query with the new column. Or you could add the column to the table you have now, then select all of its columns plus value for the new column.

You also have the option to always COALESCE the column to your desired default and leave it NULL for now. This option fails when you want NULL to have a meaning distinct from your desired default. It also requires you to depend on always remembering to COALESCE.

If you are very confident in your abilities to deal with the files backing Hive, you could also directly alter them to add your default. In general I would recommend against this because most of the time it will be slower and more dangerous. There might be some case where it makes sense though, so I've included this option for completeness.

How to remove duplicate values from a multi-dimensional array in PHP

Another way. Will preserve keys as well.

function array_unique_multidimensional($input)
    $serialized = array_map('serialize', $input);
    $unique = array_unique($serialized);
    return array_intersect_key($input, $unique);

How to search for a string in cell array in MATLAB?

did you try

indices = Find(strs, 'KU')

see link


indices = strfind(strs, 'KU');

should also work if I'm not mistaken.

Remove insignificant trailing zeros from a number?

None of these solutions worked for me for very small numbers. solved this for me.

// 1e-8

// "0.00000001"

AWS Lambda import module error in python

No need to do that mess.

use python-lambda

with single command pylambda deploy it will automatically deploy your function

What's the difference between event.stopPropagation and event.preventDefault?

Prevents the browsers default behaviour (such as opening a link), but does not stop the event from bubbling up the DOM.

Prevents the event from bubbling up the DOM, but does not stop the browsers default behaviour.

return false;
Usually seen in jQuery code, it Prevents the browsers default behaviour, Prevents the event from bubbling up the DOM, and immediately Returns from any callback.

One should checkout this really nice & easy 4 min read with examples from where the above piece was copied from.

Missing artifact com.sun:tools:jar

After struggling for a while I finally got this to work with eclipse.ini instead of the command line. After finally reading the documentation I realized that the -vm argument must be on a separate line, unquoted, and ahead of any -vmargs:

C:\Program Files\Java\jdk1.7.0_45\bin\javaw.exe

Using an if statement to check if a div is empty

if($('#leftmenu').val() == "") {
   // statement

Byte and char conversion in Java

new String(byteArray, Charset.defaultCharset())

This will convert a byte array to the default charset in java. It may throw exceptions depending on what you supply with the byteArray.

Where can I read the Console output in Visual Studio 2015

What may be happening is that your console is closing before you get a chance to see the output. I would add Console.ReadLine(); after your Console.WriteLine("Hello World"); so your code would look something like this:

static void Main(string[] args)
        Console.WriteLine("Hello World");


This way, the console will display "Hello World" and a blinking cursor underneath. The Console.ReadLine(); is the key here, the program waits for the users input before closing the console window.

How to convert wstring into string?

In my case, I have to use multibyte character (MBCS), and I want to use std::string and std::wstring. And can't use c++11. So I use mbstowcs and wcstombs.

I make same function with using new, delete [], but it is slower then this.

This can help How to: Convert Between Various String Types


However, in case of converting to wstring and source string is no alphabet and multi byte string, it's not working. So I change wcstombs to WideCharToMultiByte.

#include <string>

std::wstring get_wstr_from_sz(const char* psz)
    //I think it's enough to my case
    wchar_t buf[0x400];
    wchar_t *pbuf = buf;
    size_t len = strlen(psz) + 1;

    if (len >= sizeof(buf) / sizeof(wchar_t))
        pbuf = L"error";
        size_t converted;
        mbstowcs_s(&converted, buf, psz, _TRUNCATE);

    return std::wstring(pbuf);

std::string get_string_from_wsz(const wchar_t* pwsz)
    char buf[0x400];
    char *pbuf = buf;
    size_t len = wcslen(pwsz)*2 + 1;

    if (len >= sizeof(buf))
        pbuf = "error";
        size_t converted;
        wcstombs_s(&converted, buf, pwsz, _TRUNCATE);

    return std::string(pbuf);

EDIT to use 'MultiByteToWideChar' instead of 'wcstombs'

#include <Windows.h>
#include <boost/shared_ptr.hpp>
#include "string_util.h"

std::wstring get_wstring_from_sz(const char* psz)
    int res;
    wchar_t buf[0x400];
    wchar_t *pbuf = buf;
    boost::shared_ptr<wchar_t[]> shared_pbuf;

    res = MultiByteToWideChar(CP_ACP, 0, psz, -1, buf, sizeof(buf)/sizeof(wchar_t));

    if (0 == res && GetLastError() == ERROR_INSUFFICIENT_BUFFER)
        res = MultiByteToWideChar(CP_ACP, 0, psz, -1, NULL, 0);

        shared_pbuf = boost::shared_ptr<wchar_t[]>(new wchar_t[res]);

        pbuf = shared_pbuf.get();

        res = MultiByteToWideChar(CP_ACP, 0, psz, -1, pbuf, res);
    else if (0 == res)
        pbuf = L"error";

    return std::wstring(pbuf);

std::string get_string_from_wcs(const wchar_t* pcs)
    int res;
    char buf[0x400];
    char* pbuf = buf;
    boost::shared_ptr<char[]> shared_pbuf;

    res = WideCharToMultiByte(CP_ACP, 0, pcs, -1, buf, sizeof(buf), NULL, NULL);

    if (0 == res && GetLastError() == ERROR_INSUFFICIENT_BUFFER)
        res = WideCharToMultiByte(CP_ACP, 0, pcs, -1, NULL, 0, NULL, NULL);

        shared_pbuf = boost::shared_ptr<char[]>(new char[res]);

        pbuf = shared_pbuf.get();

        res = WideCharToMultiByte(CP_ACP, 0, pcs, -1, pbuf, res, NULL, NULL);
    else if (0 == res)
        pbuf = "error";

    return std::string(pbuf);

gcloud command not found - while installing Google Cloud SDK

So below is my previous fix for this problem, but it turns out it isn't permanent. It works but every time you restart Terminal, you'd have to do the same thing which isn't practical.

So that is why I suggest you delete the current google-cloud-sdk directory, and just redo the installation. Be sure (as Zachary has mentioned) to answer yes (Y) to the prompt Modify profile to update your $PATH and enable bash completion? (Y/n).

Here is my old answer, but just redo the installation:

I had the same problem, gcloud wasn't working for me. But then, in the same directory as my google-cloud-sdk folder which I had just installed (my home directory), I found this file called test. Inside this test file I found two commands:

# The next line updates PATH for the Google Cloud SDK.
source '[path-to-my-home]/google-cloud-sdk/'
# The next line enables bash completion for gcloud.
source '[path-to-my-home]/google-cloud-sdk/'

After I ran these two source commands in terminal, gcloud worked!

Command to get nth line of STDOUT

Yes, the most efficient way (as already pointed out by Jonathan Leffler) is to use sed with print & quit:

set -o pipefail                        # cf. help set
time -p ls -l | sed -n -e '2{p;q;}'    # only print the second line & quit (on Mac OS X)
echo "$?: ${PIPESTATUS[*]}"            # cf. man bash | less -p 'PIPESTATUS'

Copy from one workbook and paste into another

This should do it, let me know if you have trouble with it:

Sub foo()
Dim x As Workbook
Dim y As Workbook

'## Open both workbooks first:
Set x = Workbooks.Open(" path to copying book ")
Set y = Workbooks.Open(" path to destination book ")

'Now, copy what you want from x:
x.Sheets("name of copying sheet").Range("A1").Copy

'Now, paste to y worksheet:

'Close x:

End Sub

Alternatively, you could just:

Sub foo2()
Dim x As Workbook
Dim y As Workbook

'## Open both workbooks first:
Set x = Workbooks.Open(" path to copying book ")
Set y = Workbooks.Open(" path to destination book ")

'Now, transfer values from x to y:
y.Sheets("sheetname").Range("A1").Value = x.Sheets("name of copying sheet").Range("A1") 

'Close x:

End Sub

To extend this to the entire sheet:

With x.Sheets("name of copying sheet").UsedRange
    'Now, paste to y worksheet:
    y.Sheets("sheet name").Range("A1").Resize( _
        .Rows.Count, .Columns.Count) = .Value
End With

And yet another way, store the value as a variable and write the variable to the destination:

Sub foo3()
Dim x As Workbook
Dim y As Workbook
Dim vals as Variant

'## Open both workbooks first:
Set x = Workbooks.Open(" path to copying book ")
Set y = Workbooks.Open(" path to destination book ")

'Store the value in a variable:
vals = x.Sheets("name of sheet").Range("A1").Value

'Use the variable to assign a value to the other file/sheet:
y.Sheets("sheetname").Range("A1").Value = vals 

'Close x:

End Sub

The last method above is usually the fastest for most applications, but do note that for very large datasets (100k rows) it's observed that the Clipboard actually outperforms the array dump:

Copy/PasteSpecial vs Range.Value = Range.Value

That said, there are other considerations than just speed, and it may be the case that the performance hit on a large dataset is worth the tradeoff, to avoid interacting with the Clipboard.

C++ Fatal Error LNK1120: 1 unresolved externals

You must reference it. To do this, open the shortcut menu for the project in Solution Explorer, and then choose References. In the Property Pages dialog box, expand the Common Properties node, select Framework and References, and then choose the Add New Reference button.

How to get last month/year in java?

Your solution is here but instead of addition you need to use subtraction

c.add(Calendar.MONTH, -1);

Then you can call getter on the Calendar to acquire proper fields

int month = c.get(Calendar.MONTH) + 1; // beware of month indexing from zero
int year  = c.get(Calendar.YEAR);

How to get the list of all printers in computer

Look at the static System.Drawing.Printing.PrinterSettings.InstalledPrinters property.

It is a list of the names of all installed printers on the system.

Changing Jenkins build number

If you have branch name including Forward Slash (using git flow for example), you will need to replace the Forward Slash with its Unicode character %2F within the branch name.

Here is an example for the pipeline My-Pipeline-Name and the branch release/my-release-branch-name


I was able to find out about this by running the following command which will list the different jobs (branches) for your pipeline


Hope it helps.

Array versus linked-list

Other than adding and remove from the middle of the list, I like linked lists more because they can grow and shrink dynamically.

How to run Visual Studio post-build events for debug build only

Alternatively (since the events are put into a batch file and then called), use the following (in the Build event box, not in a batch file):

if $(ConfigurationName) == Debug goto :debug

signtool.exe ....
xcopy ...

goto :exit

' Debug items in here


This way you can have events for any configuration, and still manage it with the macros rather than having to pass them into a batch file, remember that %1 is $(OutputPath), etc.

What is the best method to merge two PHP objects?

I understand that using the generic objects [stdClass()] and casting them as arrays answers the question, but I thought the Compositor was a great answer. Yet I felt it could use some feature enhancements and might be useful for someone else.


  • Specify reference or clone
  • Specify first or last entry to take precedence
  • Multiple (more than two) object merging with syntax similarity to array_merge
  • Method linking: $obj->f1()->f2()->f3()...
  • Dynamic composites: $obj->merge(...) /* work here */ $obj->merge(...)


class Compositor {

    protected $composite = array();
    protected $use_reference;
    protected $first_precedence;

     * __construct, Constructor
     * Used to set options.
     * @param bool $use_reference whether to use a reference (TRUE) or to copy the object (FALSE) [default]
     * @param bool $first_precedence whether the first entry takes precedence (TRUE) or last entry takes precedence (FALSE) [default]
    public function __construct($use_reference = FALSE, $first_precedence = FALSE) {
        // Use a reference
        $this->use_reference = $use_reference === TRUE ? TRUE : FALSE;
        $this->first_precedence = $first_precedence === TRUE ? TRUE : FALSE;


     * Merge, used to merge multiple objects stored in an array
     * This is used to *start* the merge or to merge an array of objects.
     * It is not needed to start the merge, but visually is nice.
     * @param object[]|object $objects array of objects to merge or a single object
     * @return object the instance to enable linking

    public function & merge() {
        $objects = func_get_args();
        // Each object
        foreach($objects as &$object) $this->with($object);
        // Garbage collection

        // Return $this instance
        return $this;

     * With, used to merge a singluar object
     * Used to add an object to the composition
     * @param object $object an object to merge
     * @return object the instance to enable linking
    public function & with(&$object) {
        // An object
        if(is_object($object)) {
            // Reference
            if($this->use_reference) {
                if($this->first_precedence) array_push($this->composite, $object);
                else array_unshift($this->composite, $object);
            // Clone
            else {
                if($this->first_precedence) array_push($this->composite, clone $object);
                else array_unshift($this->composite, clone $object);

        // Return $this instance
        return $this;

     * __get, retrieves the psudo merged object
     * @param string $name name of the variable in the object
     * @return mixed returns a reference to the requested variable
    public function & __get($name) {
        $return = NULL;
        foreach($this->composite as &$object) {
            if(isset($object->$name)) {
                $return =& $object->$name;
        // Garbage collection

        return $return;


$obj = new Compositor(use_reference, first_precedence);
$obj->merge([object $object [, object $object [, object $...]]]);
$obj->with([object $object]);


$obj1 = new stdClass();
$obj1->a = 'obj1:a';
$obj1->b = 'obj1:b';
$obj1->c = 'obj1:c';

$obj2 = new stdClass();
$obj2->a = 'obj2:a';
$obj2->b = 'obj2:b';
$obj2->d = 'obj2:d';

$obj3 = new Compositor();
$obj3->merge($obj1, $obj2);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj2:a, obj2:b, obj1:c, obj2:d

$obj3 = new Compositor(TRUE);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj1:a, obj1:b, obj1:c, obj2:d
$obj1->c = 'obj1:c';

$obj3 = new Compositor(FALSE, TRUE);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj1:a, obj1:b, #obj1:c, obj2:d
$obj1->c = 'obj1:c';

Detecting a redirect in ajax request?

You can now use fetch API/ It returns redirected: *boolean*

How can I get the selected VALUE out of a QCombobox?

The question is old, but maybe, somebody need an actual answer.

In the QGIS 3.4 you can get the value from the QComboBox with the method currentData().

Example: comboBox.currentData()


Is there a way to override class variables in Java?

Though it is true that class variables may only be hidden in subclasses, and not overridden, it is still possible to do what you want without overriding printMe () in subclasses, and reflection is your friend. In the code below I omit exception handling for clarity. Please note that declaring me as protected does not seem to have much sense in this context, as it is going to be hidden in subclasses...

class Dad
    static String me = "dad";

    public void printMe ()
        java.lang.reflect.Field field = this.getClass ().getDeclaredField ("me");
        System.out.println (field.get (null));

How to do a simple file search in cmd

Problem with DIR is that it will return wrong answers. If you are looking for DOC in a folder by using DIR *.DOC it will also give you the DOCX. Searching for *.HTM will also give the HTML and so on...

Lua string to int

You can make an accessor to keep the "10" as int 10 in it.


x = tonumber("10")

if you print the x variable, it will output an int 10 and not "10"

same like Python process

x = int("10")


Vertical Menu in Bootstrap

With Bootstrap 2.0 you can give your tabs the "stackable" class, which makes them stack vertically.

Cannot instantiate the type List<Product>

List is an interface. You need a specific class in the end so either try

List l = new ArrayList();


List l = new LinkedList();

Whichever suit your needs.

Understanding the Gemfile.lock file

It looks to me like PATH lists the first-generation dependencies directly from your gemspec, whereas GEM lists second-generation dependencies (i.e. what your dependencies depend on) and those from your Gemfile. PATH::remote is . because it relied on a local gemspec in the current directory to find out what belongs in PATH::spec, whereas GEM::remote is, since that's where it had to go to find out what belongs in GEM::spec.

In a Rails plugin, you'll see a PATH section, but not in a Rails app. Since the app doesn't have a gemspec file, there would be nothing to put in PATH.

As for DEPENDENCIES, states:

Runtime dependencies in your gemspec are treated like base dependencies, 
and development dependencies are added by default to the group, :development

The Gemfile generated by rails plugin new my_plugin says something similar:

# Bundler will treat runtime dependencies like base dependencies, and
# development dependencies will be added by default to the :development group.

What this means is that the difference between

s.add_development_dependency "july" # (1)


s.add_dependency "july" # (2)

is that (1) will only include "july" in Gemfile.lock (and therefore in the application) in a development environment. So when you run bundle install, you'll see "july" not only under PATH but also under DEPENDENCIES, but only in development. In production, it won't be there at all. However, when you use (2), you'll see "july" only in PATH, not in DEPENDENCIES, but it will show up when you bundle install from a production environment (i.e. in some other gem that includes yours as a dependency), not only development.

These are just my observations and I can't fully explain why any of this is the way it is but I welcome further comments.

Error: Could not find or load main class in intelliJ IDE

I am working with Kotlin but am guessing the problem is the same. I would start a project, create a single file and add main to it and the IDE couldn't find the main.

I tried the things in this list and none worked. I finally mentioned my frustration on one of the IntelliJ pages and was contacted. Of course, it worked fine for IntelliJ. After a couple of days back and forth, I noticed that the highlight function wasn't working and mentioned that. It turned out something was wrong with the IDE settings. I still don't know specifically what was wrong but the fix in my case was to reset the IDE settings. File->Manage IDE Settings->Restore Default settings.

After this, the green triangle start icon became visible to the left of my main function and things continued to work normally for subsequent projects.
Thanks to Konstantin at JetBrain's support for his patience.

Remove file extension from a file name string

I know it's an old question and Path.GetFileNameWithoutExtensionis a better and maybe cleaner option. But personally I've added this two methods to my project and wanted to share them. This requires C# 8.0 due to it using ranges and indices.

public static string RemoveExtension(this string file) => ReplaceExtension(file, null);

public static string ReplaceExtension(this string file, string extension)
    var split = file.Split('.');

    if (string.IsNullOrEmpty(extension))
        return string.Join(".", split[..^1]);

    split[^1] = extension;

    return string.Join(".", split);

Proper way to declare custom exceptions in modern Python?

Maybe I missed the question, but why not:

class MyException(Exception):

Edit: to override something (or pass extra args), do this:

class ValidationError(Exception):
    def __init__(self, message, errors):

        # Call the base class constructor with the parameters it needs
        super(ValidationError, self).__init__(message)

        # Now for your custom code...
        self.errors = errors

That way you could pass dict of error messages to the second param, and get to it later with e.errors

Python 3 Update: In Python 3+, you can use this slightly more compact use of super():

class ValidationError(Exception):
    def __init__(self, message, errors):

        # Call the base class constructor with the parameters it needs

        # Now for your custom code...
        self.errors = errors

SSRS custom number format

You can use


Get value of input field inside an iframe

Without Iframe We can do this by JQuery but it will give you only HTML page source and no dynamic links or html tags will display. Almost same as php solution but in JQuery :) Code---

var purl = "";
$.getJSON('' +
    encodeURIComponent(purl) + '&callback=?',
    function (data) {

Chrome extension: accessing localStorage in content script

Update 2016:

Google Chrome released the storage API:

It is pretty easy to use like the other Chrome APIs and you can use it from any page context within Chrome.

    // Save it using the Chrome extension storage API.{'foo': 'hello', 'bar': 'hi'}, function() {
      console.log('Settings saved');

    // Read it using the storage API['foo', 'bar'], function(items) {
      message('Settings retrieved', items);

To use it, make sure you define it in the manifest:

    "permissions": [

There are methods to "remove", "clear", "getBytesInUse", and an event listener to listen for changed storage "onChanged"

Using native localStorage (old reply from 2011)

Content scripts run in the context of webpages, not extension pages. Therefore, if you're accessing localStorage from your contentscript, it will be the storage from that webpage, not the extension page storage.

Now, to let your content script to read your extension storage (where you set them from your options page), you need to use extension message passing.

The first thing you do is tell your content script to send a request to your extension to fetch some data, and that data can be your extension localStorage:


chrome.runtime.sendMessage({method: "getStatus"}, function(response) {


chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if (request.method == "getStatus")
      sendResponse({status: localStorage['status']});
      sendResponse({}); // snub them.

You can do an API around that to get generic localStorage data to your content script, or perhaps, get the whole localStorage array.

I hope that helped solve your problem.

To be fancy and generic ...


chrome.runtime.sendMessage({method: "getLocalStorage", key: "status"}, function(response) {


chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if (request.method == "getLocalStorage")
      sendResponse({data: localStorage[request.key]});
      sendResponse({}); // snub them.

React.js create loop through Array

As @Alexander solves, the issue is one of async data load - you're rendering immediately and you will not have participants loaded until the async ajax call resolves and populates data with participants.

The alternative to the solution they provided would be to prevent render until participants exist, something like this:

    render: function() {
        if (! {
            return null;
        return (
            <ul className="PlayerList">
            // I'm the Player List {}
            // <Player author="The Mini John" />
                    return <li key={player}>{player}</li>

jQuery get textarea text

Normally, it's the value property


Or is there something I'm missing in what you need?

CSS flex, how to display one item on first line and two on the next line

The answer given by Nico O is correct. However this doesn't get the desired result on Internet Explorer 10 to 11 and Firefox.

For IE, I found that changing

.flex > div
   flex: 1 0 50%;


.flex > div
   flex: 1 0 45%;

seems to do the trick. Don't ask me why, I haven't gone any further into this but it might have something to do with how IE renders the border-box or something.

In the case of Firefox I solved it by adding

display: inline-block;

to the items.

jQuery - Click event on <tr> elements with in a table and getting <td> element values

$("body").on("click", "#tableid tr", function () {

$("body").on("click", "#tableid td", function () {

JSON Parse File Path

Loading local JSON file

Use something like this

$.getJSON("../../data/file.json", function(json) {
    console.log(json); // this will show the info in firebug console 

How to open google chrome from terminal?

Use command


We can also use command


To open terminal but in my case when I make an interrupt ctrl + c then it get closed so I would recommend to use google-chrome-stable instead of google-chrome

MongoDB: How to query for records where field is null or not set?

You can also try this:


Can I replace groups in Java regex?

You can use matcher.start() and matcher.end() methods to get the group positions. So using this positions you can easily replace any text.

successful/fail message pop up box after submit?

You are echoing outside the body tag of your HTML. Put your echos there, and you should be fine.

Also, remove the onclick="alert()" from your submit. This is the cause for your first undefined message.

  $posted = false;
  if( $_POST ) {
    $posted = true;

    // Database stuff here...
    // $result = mysql_query( ... )
    $result = $_POST['name'] == "danny"; // Dummy result


    if( $posted ) {
      if( $result ) 
        echo "<script type='text/javascript'>alert('submitted successfully!')</script>";
        echo "<script type='text/javascript'>alert('failed!')</script>";
    <form action="" method="post">
      Name:<input type="text" id="name" name="name"/>
      <input type="submit" value="submit" name="submit"/>

Android translate animation - permanently move View to new position using AnimationListener

This is what worked for me perfectly:-

// slide the view from its current position to below itself
public void slideUp(final View view, final View llDomestic){

    ObjectAnimator animation = ObjectAnimator.ofFloat(view, "translationY",0f);


// slide the view from below itself to the current position
public void slideDown(View view,View llDomestic){
    ObjectAnimator animation = ObjectAnimator.ofFloat(view, "translationY",   0f);

llDomestic : The view which you want to hide. view: The view which you want to move down or up.

Does uninstalling a package with "pip" also remove the dependent packages?

I have found the solution even though it might be a little difficult for some to carry out.

1st step (for python3 and linux):
pip3 install pip-autoremove
2nd step:
cd /home/usernamegoeshere/.local/bin/
3rd step:
gedit /home/usernamegoeshere/.local/lib/python3.8/site-packages/
and change all pip(s) to pip3 4th step: ./pip-autoremove packagenamegoeshere

At least, this was what worked for me ...

Angular2: How to load data before rendering the component?



When console.log(this.ev) is executed after this.fetchEvent();, this doesn't mean the fetchEvent() call is done, this only means that it is scheduled. When console.log(this.ev) is executed, the call to the server is not even made and of course has not yet returned a value.

Change fetchEvent() to return a Promise

        return  this._apiService.get.event(this.eventId).then(event => {
            this.ev = event;
            console.log(event); // Has a value
            console.log(this.ev); // Has a value

change ngOnInit() to wait for the Promise to complete

    ngOnInit() {
        this.fetchEvent().then(() =>
        console.log(this.ev)); // Now has value;

This actually won't buy you much for your use case.

My suggestion: Wrap your entire template in an <div *ngIf="isDataAvailable"> (template content) </div>

and in ngOnInit()

    isDataAvailable:boolean = false;

    ngOnInit() {
        this.fetchEvent().then(() =>
        this.isDataAvailable = true); // Now has value;

How to go up a level in the src path of a URL in HTML?

Use ../:

background-image: url('../images/bg.png');

You can use that as often as you want, e.g. ../../images/ or even at different positions, e.g. ../images/../images/../images/ (same as ../images/ of course)

Cross-browser custom styling for file upload button

I'm posting this because (to my surprise) there was no other place I could find that recommended this.

There's a really easy way to do this, without restricting you to browser-defined input dimensions. Just use the <label> tag around a hidden file upload button. This allows for even more freedom in styling than the styling allowed via webkit's built-in styling[1].

The label tag was made for the exact purpose of directing any click events on it to the child inputs[2], so using that, you won't require any JavaScript to direct the click event to the input button for you anymore. You'd to use something like the following:

label.myLabel input[type="file"] {_x000D_
    top: -1000px;_x000D_
/***** Example custom styling *****/_x000D_
.myLabel {_x000D_
    border: 2px solid #AAA;_x000D_
    border-radius: 4px;_x000D_
    padding: 2px 5px;_x000D_
    margin: 2px;_x000D_
    background: #DDD;_x000D_
    display: inline-block;_x000D_
.myLabel:hover {_x000D_
    background: #CCC;_x000D_
.myLabel:active {_x000D_
    background: #CCF;_x000D_
.myLabel :invalid + span {_x000D_
    color: #A44;_x000D_
.myLabel :valid + span {_x000D_
    color: #4A4;_x000D_
<label class="myLabel">_x000D_
    <input type="file" required/>_x000D_
    <span>My Label</span>_x000D_

I've used a fixed position to hide the input, to make it work even in ancient versions of Internet Explorer (emulated IE8- refused to work on a visibility:hidden or display:none file-input). I've tested in emulated IE7 and up, and it worked perfectly.

  1. You can't use <button>s inside <label> tags unfortunately, so you'll have to define the styles for the buttons yourself. To me, this is the only downside to this approach.
  2. If the for attribute is defined, its value is used to trigger the input with the same id as the for attribute on the <label>.

How can I determine the character encoding of an excel file?

For Excel 2010 it should be UTF-8. Instruction by MS :

"The basic document structure of a SpreadsheetML document consists of the Sheets and Sheet elements, which reference the worksheets in the Workbook. A separate XML file is created for each Worksheet. For example, the SpreadsheetML for a workbook that has two worksheets name MySheet1 and MySheet2 is located in the Workbook.xml file and is shown in the following code example.

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?> 
<workbook xmlns= xmlns:r="">
        <sheet name="MySheet1" sheetId="1" r:id="rId1" /> 
        <sheet name="MySheet2" sheetId="2" r:id="rId2" /> 

The worksheet XML files contain one or more block level elements such as SheetData. sheetData represents the cell table and contains one or more Row elements. A row contains one or more Cell elements. Each cell contains a CellValue element that represents the value of the cell. For example, the SpreadsheetML for the first worksheet in a workbook, that only has the value 100 in cell A1, is located in the Sheet1.xml file and is shown in the following code example.

<?xml version="1.0" encoding="UTF-8" ?> 
<worksheet xmlns="">
        <row r="1">
            <c r="A1">


Detection of cell encodings:

Change the encoding of a file in Visual Studio Code

The existing answers show a possible solution for single files or file types. However, you can define the charset standard in VS Code by following this path:

File > Preferences > Settings > Encoding > Choose your option

This will define a character set as default. Besides that, you can always change the encoding in the lower right corner of the editor (blue symbol line) for the current project.

center aligning a fixed position div

Normal divs should use margin-left: auto and margin-right: auto, but that doesn't work for fixed divs. The way around this is similar to Andrew's answer, but doesn't use the deprecated <center> thing. Basically, just give the fixed div a wrapper.

#wrapper {_x000D_
    width: 100%;_x000D_
    position: fixed;_x000D_
    background: gray;_x000D_
#fixed_div {_x000D_
    margin-left: auto;_x000D_
    margin-right: auto;_x000D_
    position: relative;_x000D_
    width: 100px;_x000D_
    height: 30px;_x000D_
    text-align: center;_x000D_
    background: lightgreen;_x000D_
<div id="wrapper">_x000D_
    <div id="fixed_div"></div>_x000D_

This will center a fixed div within a div while allowing the div to react with the browser. i.e. The div will be centered if there's enough space, but will collide with the edge of the browser if there isn't; similar to how a regular centered div reacts.

How do I get the current username in .NET using C#?

In case it's helpful to others, when I upgraded an app from 3.5 app to Visual Studio 2017 this line of code User.Identity.Name.Substring(4); threw this error "startIndex cannot be larger than length of string" (it didn't baulk before).

It was happy when I changed it to System.Security.Principal.WindowsIdentity.GetCurrent().Name however I ended up using Environment.UserName; to get the logged in Windows user and without the domain portion.

How to plot a very simple bar chart (Python, Matplotlib) using input *.txt file?

You're talking about histograms, but this doesn't quite make sense. Histograms and bar charts are different things. An histogram would be a bar chart representing the sum of values per year, for example. Here, you just seem to be after bars.

Here is a complete example from your data that shows a bar of for each required value at each date:

import pylab as pl
import datetime

data = """0 14-11-2003
1 15-03-1999
12 04-12-2012
33 09-05-2007
44 16-08-1998
55 25-07-2001
76 31-12-2011
87 25-06-1993
118 16-02-1995
119 10-02-1981
145 03-05-2014"""

values = []
dates = []

for line in data.split("\n"):
    x, y = line.split()
    dates.append(datetime.datetime.strptime(y, "%d-%m-%Y").date())

fig = pl.figure()
ax = pl.subplot(111), values, width=100)

You need to parse the date with strptime and set the x-axis to use dates (as described in this answer).

If you're not interested in having the x-axis show a linear time scale, but just want bars with labels, you can do this instead:

fig = pl.figure()
ax = pl.subplot(111), values)

EDIT: Following comments, for all the ticks, and for them to be centred, pass the range to set_ticks (and move them by half the bar width):

fig = pl.figure()
ax = pl.subplot(111)
width=0.8, values, width=width)
ax.set_xticks(np.arange(len(dates)) + width/2)
ax.set_xticklabels(dates, rotation=90)

Any reason to prefer getClass() over instanceof when generating .equals()?

instanceof works for instences of the same class or its subclasses

You can use it to test if an object is an instance of a class, an instance of a subclass, or an instance of a class that implements a particular interface.

ArryaList and RoleList are both instanceof List


getClass() == o.getClass() will be true only if both objects ( this and o ) belongs to exactly the same class.

So depending on what you need to compare you could use one or the other.

If your logic is: "One objects is equals to other only if they are both the same class" you should go for the "equals", which I think is most of the cases.

Django. Override save for model

Check the model's pk field. If it is None, then it is a new object.

class Model(model.Model):

    def save(self, *args, **kwargs):
        if 'form' in kwargs:

        if is None and form is not None and 'image' in form.changed_data:
        super(Model, self).save(*args, **kwargs)

Edit: I've added a check for 'image' in form.changed_data. This assumes that you're using the admin site to update your images. You'll also have to override the default save_model method as indicated below.

class ModelAdmin(admin.ModelAdmin):
    def save_model(self, request, obj, form, change):

ADB Driver and Windows 8.1

There is lots of stuff on this topic, each slightly different. Like many users I spent hours trying them and got nowhere. In the end, this is what worked for me - I.e. installed the driver on windows 8.1

In my extras/google/usb_driver is a file android_winusb.inf

I double clicked on this and it "ran" and installed the driver.

I can't explain why this worked.

Javascript - Regex to validate date format

You can use regular multiple expressions with the use of OR (|) operator.

function validateDate(date){
    var regex=new RegExp("([0-9]{4}[-](0[1-9]|1[0-2])[-]([0-2]{1}[0-9]{1}|3[0-1]{1})|([0-2]{1}[0-9]{1}|3[0-1]{1})[-](0[1-9]|1[0-2])[-][0-9]{4})");
    var dateOk=regex.test(date);
        alert("not Ok");

Above function can validate YYYY-MM-DD, DD-MM-YYYY date formats. You can simply extend the regular expression to validate any date format. Assume you want to validate YYYY/MM/DD, just replace "[-]" with "[-|/]". This expression can validate dates to 31, months to 12. But leap years and months ends with 30 days are not validated.

How to change the hosts file on android

That didn't really work in my case - i.e. in order to overwrite hosts file you have to follow it's directions, ie:

./emulator -avd myEmulatorName -partition-size 280

and then in other term window (pushing new hosts file /tmp/hosts):

./adb remount
./adb push /tmp/hosts /system/etc

jQuery add text to span within a div

Careful - append() will append HTML, and you may run into cross-site-scripting problems if you use it all the time and a user makes you append('<script>alert("Hello")</script>').

Use text() to replace element content with text, or append(document.createTextNode(x)) to append a text node.

How to plot a subset of a data frame in R?

Most straightforward option:


It does not look good because of code redundancy, but is ok for fastndirty hacking.

Retina displays, high-res background images

If you are planing to use the same image for retina and non-retina screen then here is the solution. Say that you have a image of 200x200 and have two icons in top row and two icon in bottom row. So, it's four quadrants.

.sprite-of-icons {
  background: url("../images/icons-in-four-quad-of-200by200.png") no-repeat;
  background-size: 100px 100px /* Scale it down to 50% rather using 200x200 */

.sp-logo-1 { background-position: 0 0; }

/* Reduce positioning of the icons down to 50% rather using -50px */
.sp-logo-2 { background-position: -25px 0 }
.sp-logo-3 { background-position: 0 -25px }
.sp-logo-3 { background-position: -25px -25px }

Scaling and positioning of the sprite icons to 50% than actual value, you can get the expected result.

Another handy SCSS mixin solution by Ryan Benhase.


@mixin background-2x($path, $ext: "png", $w: auto, $h: auto, $pos: left top, $repeat: no-repeat) {

  $at1x_path: "#{$path}.#{$ext}";
  $at2x_path: "#{$path}@2x.#{$ext}";

  background-image: url("#{$at1x_path}");
  background-size: $w $h;
  background-position: $pos;
  background-repeat: $repeat;

  @media all and (-webkit-min-device-pixel-ratio : 1.5),
  all and (-o-min-device-pixel-ratio: 3/2),
  all and (min--moz-device-pixel-ratio: 1.5),
  all and (min-device-pixel-ratio: 1.5) {
    background-image: url("#{$at2x_path}"); 

div.background {
  @include background-2x( 'path/to/image', 'jpg', 100px, 100px, center center, repeat-x );

For more info about above mixin READ HERE.

How to resize an Image C#

This will perform a high quality resize:

/// <summary>
/// Resize the image to the specified width and height.
/// </summary>
/// <param name="image">The image to resize.</param>
/// <param name="width">The width to resize to.</param>
/// <param name="height">The height to resize to.</param>
/// <returns>The resized image.</returns>
public static Bitmap ResizeImage(Image image, int width, int height)
    var destRect = new Rectangle(0, 0, width, height);
    var destImage = new Bitmap(width, height);

    destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);

    using (var graphics = Graphics.FromImage(destImage))
        graphics.CompositingMode = CompositingMode.SourceCopy;
        graphics.CompositingQuality = CompositingQuality.HighQuality;
        graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
        graphics.SmoothingMode = SmoothingMode.HighQuality;
        graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;

        using (var wrapMode = new ImageAttributes())
            graphics.DrawImage(image, destRect, 0, 0, image.Width,image.Height, GraphicsUnit.Pixel, wrapMode);

    return destImage;
  • wrapMode.SetWrapMode(WrapMode.TileFlipXY) prevents ghosting around the image borders -- naïve resizing will sample transparent pixels beyond the image boundaries, but by mirroring the image we can get a better sample (this setting is very noticeable)
  • destImage.SetResolution maintains DPI regardless of physical size -- may increase quality when reducing image dimensions or when printing
  • Compositing controls how pixels are blended with the background -- might not be needed since we're only drawing one thing.
  • graphics.InterpolationMode determines how intermediate values between two endpoints are calculated
  • graphics.SmoothingMode specifies whether lines, curves, and the edges of filled areas use smoothing (also called antialiasing) -- probably only works on vectors
  • graphics.PixelOffsetMode affects rendering quality when drawing the new image

Maintaining aspect ratio is left as an exercise for the reader (actually, I just don't think it's this function's job to do that for you).

Also, this is a good article describing some of the pitfalls with image resizing. The above function will cover most of them, but you still have to worry about saving.